My living situation means getting to a Gym is just about impossible (and more expensive then I can afford). My off-season (off the bike) involves skiing once or twice a week depending on mood. My work provides me with a free season pass (I work for a ski company) otherwise I probably wouldn't be able to afford one myself. I am not that into skiing as most people, so usually only ski on one of my 2 days off a week. I've heard cross country skiing is also a good off-season work out and might be more feasible when it comes to cost.
So, what I like about the rollers is that they don't chew up a tire as badly as a trainer. But then there is the space issue - won't fit in my room but should be able to fit in the comman area of the house i live in, by the TV. A trainer is much more compact and would easily fit in most places I think, but would require getting a new rear wheel to avoid shredding my road tire. So I think I am leaning towards the rollers at this point.