Weird to see how Mystery Dungeon was an unpopular series until now.
I used to play the main series a lot, but when DPP came out I kinda lost interest, and the newer games are total garbage. (It's hard for me to mention those games without getting upset) Same thing with the Mystery Dungeon series, there was that thing called Gates to Infinity that is comparable to an heresy. While I enjoyed Firered, this game being a huge portion of my childhood, when I got my first Mystery Dungeon, I played it so much, that one of the components Inside overheated and broke; I am not even kidding. Eventually I bought it back and I am still playing on occasions, as I focus on Melee and Skyrim. I also played the Explorers, but never owned one. I plan to buy Explorers of Sky soon tho.
While I friggin love those games, I doubt they have a great future, as Nintendo is turning the main series to a childish non-difficult game, and that they completly annihilated the series with their first 3DS installment for the Mystery Dungeon series. But I'm going to get Super Mystery Dungeon tonight, and it's actually the last chance for Nintendo to bring me back, or I'll just leave and play my old games.
One thing: I couldn't care less for graphics, I just don't. Just give me a good game, and don't give me some garbage from your impressionalist culture!
Edit: Forgot my answer lol: Mystery Dungeon ftw! They offer a much better gameplay and story than the main games, and it is actually very challenging.