Well I'm a diehard Korg fan, but the M1 is fairly outdated (Still a great old synth though), XP-30 pretty much sucks (IMO), I've only played Juno-D briefly, and it felt kind of cheap to me, so I'm going with S-03 (Lack of aftertouch and sequencer and all). But if these were my only choices, I wouldn't buy any of them, I'd save my money until I could afford more choices. You could get a used Triton LE probably for what you'd pay for any of these.
(I'll sit patiently and wait for the KFC (Kurzweil Fan Club) to chime in)
So far, so good. The Juno-D has show some nice drums and pianos. And has some of the Juno-II sounds, so I happy. Arp's a little strange, but I think I'm starting to understand it. The manual seems to had been written in Language instead of Random Word Placement.
Glad you like it. I'm mostly peaved that Roland slapped a brand name on a synth that so obviously doesn't deserve it, just to sell more units (a la Car Manufacturer Style ).
I liked the Alesis Micron too. Have not heard alot of the other synths recently. Some of them are likely very nice. To be fair I only played with the micron for about 10 minutes.