I started with a Roland XP-30, added a 2020, then dumped them both and went to
a XV-3080. I don't know much about
the XV-5050, but from what I understand the 3080 and the 5050 are pretty close. I will never be without a Roland synth though - they are the workhorse of many a studio, and those who dig in and get familiar with them eventually cone to a point that they can't live without one. Or two. And some expansion cards.
I also purchased a Triton Rack a while back, and used it for about 6 months. Maybe it's the style of music I'm writing (modern symphonic, world fusion, funk, etc.), but the Triton was a major disapointment. I ended up selling it off and replacing it with some Roland expansions.
Some things to consider though...
The Triton has a sampler built-in. If you need a sampler, it's a decent all-in-one unit. If you want a separate synth and sampler, check out
the Akai Z4/Z8. Roland also has a synth/sampler combo,
the XV-5080.
For stock patches my experience has been that the Triton has better all-around drums than most Roland synths. Head to head, with no expansions, the Triton kicks some major tail in the rhythm department as a whole.
Put some thought into expansion cards. They are fairly cheap, and are a great way to expand your library without having to pick up more synths. I've found that Roland is really great about releasing new cards regularly. The 5050 uses the new SRX cards too, and that line of cards will continue to grow over the next couple of years. The triton, likewise, has some nice expansions, but there aren't any new ones coming out for that line, that I know of.
Find a dealer in your area and see if you can demo each of the units you're interested in for a week. They'll put a hold on your credit card for the duration of the demo, but it'll give you a chance to see which one suits you best. Always try before you buy. I made the mistake of buying the Triton without picking up a demo first, and it bit me on the ass.
-Jesse
