Definitely Smash 4 as it's looking to be a lot more competitive than Brawl was in the long run. That said, some people in the melee/PM communities are bad seeds if not outright cancerous to the smash bros community(Leffen anybody?) as a whole though the other communities do have their fair share of bad seeds as well. Also many Melee/PM fans are at least willing to give 3DS/Wii U a shot for the next few months/year. That I feel speaks volumes about how resistant to change the Melee community isn't. Now if some of these players end up going back to Melee/PM, their loss. The huge influx of new players 4 will be getting anyway in the coming months/year alone will more than make up for it.
However with that said, if some of these same players start using their preference in smash bros game as an excuse to ignorantly bash/insult/flamebait the Smash 4 community, that sort of behavior cannot and WILL NOT be tolerated! It was bad enough that the Brawl era left a gigantic rift in the community the size of the Great Canyon complete with certain Melee players who will remain nameless that went out of their way to make Brawl players feel stupid for not liking a game that's "obviously better than that casual crap you play" and make the game as a whole look uninteresting on purpose by camping/stalling out matches and then try to use that as "proof" of their biased convictions later on resulting in an even stronger Brawl community who justifiably wanted and still don't want anything to do at all with the game who's fanbase mercilessly bullied them just because their taste in games was different.
Long story short, we don't need another humongous, childish, and very petty like schism in the smash bros community. Project M I feel helped improve relations between the Melee and Brawl crowds a bit though that game itself has been rife with controversy between the two groups. (Some Melee players have still stuck to Melee which is fine, yet some of them also bashed on PM for a multitude of reasons ranging from reasonable to asinine the latter of which is not fine. Some Brawl players likewise have whined about PM for being a sped up more balanced version of Brawl and feel its somehow an insult to their community
I don't think anybody who was around for the Melee VS Brawl wars wants to relive all that drama with Melee/PM VS Smash 4 which unfortunately I've already seen a bit of here and there and 4 hasn't even been out a month yet not to mention the Wii U version still doesn't have an officially confirmed release date yet. (though many speculate around Black Friday as a potential release date). As I previously mentioned, only some Melee/PM fans in their respective communities are bad seeds and the other communities are more or less the same in that regard, but it was mostly the Melee community who started the lion's share drama/flame wars back during the Brawl era. Ignoring any bad seeds from the Brawl community who intentionally started **** with the Melee community, the Brawl community might not have been any better for lashing out at the Melee community for acting like jerks towards them, but can you blame them for it? Its like a kid who always gets bullied at school finally making the bully(ies) feel terrible about himself rather than the other way around, yet the former is the one who always gets in the most trouble even though he had a justifiable reason for fighting back against said tormentor.
With PM's wild success with the community, we've been seeing an influx of new players and the return of a few oldies too! That is a great thing for the community. However, I think we can all agree it hasn't been all sunshine and roses as PM has unintentionally resurrected Melee VS Brawl flame wars of old and with Melee's recent revival in the competitive scene from small grassroot events to the likes of MLG/EVO, the wounds from both sides has only been made worse and 4 is sadly feeling the effects of the Melee VS Brawl schism. I honestly can't seem to go ANYWHERE on the internet where smash bros is being discussed and not run across that one guy who's into Melee/PM complete with a "holier than thou" attitude/ego that takes time out of his day to flamebait Brawl and even 3DS/Wii fans by making a rash tactless comment about how much better Melee/PM is and how 4 will supposedly crash and burn not too long after release or just a generally nasty comment that serves no purpose other than get people riled up enough to reply (i.e a troll comment if you will)
Its fine if you think Melee/PM is great. Its fine if 4 isn't looking to be your cup of tea, we won't miss you one bit I promise! Its NOT fine if you intentionally bait people by typing a crap/unpopular opinion you know for a fact is going to get mass hate from more logical and sensible denizens of the internet. Keep those type of opinions to yourself as all it does is start drama and in places with a moderator team give them a headache as they have to take time out of their otherwise enjoyable day by handing out warning/infractions more often than not to the same type of people over and over again. Smash 4 is without a shadow of a doubt going to be the main smash bros event at next years EVO/MLG as it would look very bad from a business standpoint if Melee continued to hog all the attention or even so much as co-exist with 4 at the highest levels of play (smaller grassroot events like Apex would be fine however as not as many people know about those and mass amounts of money is usually not at stake). Nintendo was generous enough to let Melee be streamed at EVO 2013 and support it at this years EVO, but with 4 being their latest entry in the series, they are going to push it as much as possible to be the main competitive game. That is fine as the big N is a business. It would be weird if they didn't.
Like it or not, Melee will probably NOT be the main event at next years EVO/MLG nor will it likely be able to co-exist with 4 at said high level tournaments with lots of viewership as it would unfair to overshadow 4 this early into it's competitive run and thus unintentionally prove the stereotype about the Melee community being stuck in their ways and hissing at the mere thought of adapting to a new game true. Should Nintendo declare/confirm that 3DS/Wii U will be the only smash bros game featured at EVO 2015, that is first and foremost their decision to make, NOT YOURS or ANY OF US'S decision. Melee has proven it will never die no matter what and still being played at smaller and/or tournaments run by the community is all we can ask for. All I and many other people ask for in return is that most if not all of us can be amicable and supportive towards 4 and its own competitive scene and not resort to being complete assholes just because of whatever childish/stupid reason you come up with for being that way towards 4 and its fan base.
Remember, a schism like the one Brawl left in its wake that some of the Melee community only made worse with their words and actions is never healthy for a community and so help me god if another one gets started courtesy of some of the more bitter "fans" of Melee/PM and proceeds to spiral out of control just as bad as Melee VS Brawl if not worse, my suggestion would be to punish the entire communities for Melee and Project M by forbidding those two games at the higher level tournaments which would hit them exactly where it hurts! At least until said communities purged themselves of all the truly bad seeds who started and continued to be unsportsmanlike towards 4. It wouldn't be a popular move yes, but if that's what it takes to get the entire community to grow the hell up and learn to appreciate 4 even if its not their choice of competitive game, then so be it!
That is my two cents on this thread and the future of the smash bros community. Again, If some of the Melee/PM fans aren't on board with 3DS/Wii U, that's fine so long as they don't go starting **** with us like some of the same people in the Melee community did with Brawl back in the day. We as a community are (hopefully) wiser now than we were a few years back and if 4 is to make a name for itself minus all the drama/controversy Brawl had to put with during its run, we need to let smash 4 detractors who repeatedly start drama for the lulz know the rules of being a good sport and the subsequent consequences that shall follow if said rules are repeatedly violated.