Little did i know you were a little bit of a asshole.
This is a recently found commercial dance track with gameboy music in from 1994 (may even be earlier according to the comments), that predates a ton of stuff even if it is just a sample of Super Mario Land. (hence the 'mario at a rave' comment, which is a chipmusic meme but in this case can genuinely be used to describe the song in question) Finding stuff like this all adds to the history of the scene don't you think? Have you not read chipflip?
C64 and XL have different sound chips yes, but there's a broad similarity in the types of sound chips they have. (witness Rob Hubbard's work on both systems) On the Atari side the sound is a bit more "harsh" and you don't get filters, but they're both pretty nice chips to experiment with.
Both systems use a version of the 65xx processor so if you learn assembly on one you can adapt it for another. Personally I'd say buy the c64 because there's a ton more editors and so on there, and the community is (arguably) more active.
That is pretty cool! I hope it doesn't end up like OGG; where it is technically quite nice, but finds little use outside of enthusiast or technical communities, and has little to no hardware support.
OGG (and CELT for that matter) are used in tons of games, it saves having to pay license fees for other codecs.
MPT interface is weird, and I don't know much about milkytracker.
but FT2 has the best tracker interface ever IMO.
I don't mean to be "that dude," but have you ever used Renoise? It has an FT2-style interface (with many improvements) and all the benefits of a modern DAW.