ZX is a little better than Advent in my opinion.

I didn't think the games were nearly as good as the Megaman Zero or the Megaman X series.

 

I thought Advent was better than ZX purely for having an improved map system. It was too easy to get lost in ZX if you didn't know what you were doing.

As for what's better out of Battle Network 5 & the Star Force games, it's all really a matter of taste. I prefer the battle system from the Battle Network games myself, but unless you're really obsessive about the smaller differences between the titles, you only really need to get one anyway.

That said though, as previous posters pointed out, none of these quite compare to the NES originals, SNES Megaman Xs 1-3, GBA Battle Networks 1,2,3 & 6 or the GBA Megaman Zero games.

 

Megaman & Bass is my favorite - if it's emulateable on SnesDS

 

The best for me was SNES Megaman X. My second favorite was Megaman V for gameboy.

 

There is??? USA version?

 

Yes, there is USA version of Megaman & Bass (one of the few games I bought for the GBA alongside with FFTA). I´m a proud owner of the MM2 of nes, and I agree is one of the best games. For GBA I prefer the Zero saga (mmz3) and MMBN 6. For DS, I prefer ZX than Advent, some bosses are really hard (and without recovery in the final stage)

 

MM2 - NES
MM7 - SNES

Those are my two favorites..

 

As well as the most badass of codes. Holding A+B as you select a boss level, and instead of stars behind the boss animation...

Warning: Spoilers inside!

YOU GET LITTLE BIRDIES!!!

 

the whole Rockman.exe series is great !