The level speed modifier works wonders! It's probably one of the best codes for Brawl+, because it opens the door for so many maps!
I've experienced a few oddities with the code, though it wasn't a problem, just certain stages don't perform well with it. Namely, Shadow Moses Island. Once either one of the two columns are destroyed.. they don't go away, yet you can still walk through them as if they are gone. To make things worse, the screen keeps shaking because the columns glitch up and made the collapse noise repeatedly.
Otherwise, the code works flawlessly. I don't like the new Pokemon Stadium for example, I find the treadmills and gravity modifier of the stage to be rediculous, yet I love the original stage. What's awesome, is now, with the code, I can freeze the new Pokemon Stadium so that it won't transform. It'll stay as the regular stadium the entire match, being a good neutral stage. It's comparable to FD, Battlefield, and Smashville now.
Also, I've had no problems with the Warioware level with this code, it worked flawlessly. This map is also a great map now, in its neutral state. With that said, Pictochat is another unique map in that it's flat like FD, but without the weird edges. It has a walled bottom so that characters can wall cling (Lucario). So this map is great now.
There are so many great levels now, I love it.
TL:DR
•Level Speed Modifier = a must for Brawl+
•More playable maps = win
•Pictochat / Pokemon Stadium 2 / Warioware all look to be great neutral maps -- comparable with FD Battefield and Smashvilled (to name a few).
•I never experienced any bugs with the code, like crashing, or freezing, and I used it on many of the maps.
•Pirate Ship is now a great map without all of the hazards-- it is really interesting!
@Almas, what do you mean "nothing seemed to go away" with regards to warioware? I've played it a ton with the code and it works perfectly well. At start, it freezes with a pig picture in the background, and the 4 raised platforms. It's worked perfectly for me each time I've played it.