today i was just about to buy a nimbus seat from unicycle.com but then i saw the schwinn gel seat for the same price what should i get? 
I’m pretty sure that the Schwinn gel seat is the same as the pre-2010 Nimbus gel seat. In other words it has the same base as the Nimbus Hi-Top but with a lower profile, and gel padding. You could call UDC to make sure, but I seem to remember something about the new run of Schwinn uni’s being licensed by UDC from Pacific cycles, and it wouldn’t make sense that they make a completely new saddle for it.
As for a recommendation, well that is too much of a personal preference thing to be helpful. It seems like saddle are generally getting slimmer and so in that regard the Schwinn seat may be a better choice. The Nimbus Hi-Top is basically the same as the original KH Fusion and they moved away from that much foam 3 or 4 years ago.
What are you using it for? MUni, freestyle, street, flat, commuting etc? I imagine that would make a big difference.
The KH Freeride is supposed to be a good saddle, but I’ve never tried one so I can’t give a personal recommendation. I generally use the bog standard Qu-Ax saddles - they get the job done but they’re nothing special and I’m sure there are better options out there.
Their flame saddle (check out the link in my sig) looks pretty sweet but it’s a bit on the small side and rather firm… 
So far the Nimbus gel has been my favorite seat. I also have a Fusion Freeride (09 I think) and Nimbus Club. I haven’t put enough time on the club to say much about it but what little time I have on it has been positive.
The only thing I don’t like is that the Nimbus gel is its fat between the legs. After I ride my inner legs are sore (but not chafed like with the freeride) and the pain goes away quickly once i’m off the uni. Someday I may take the cover off and remove some foam if I can figure out how to reattach the cover.
My experiences with the Freeride have not matched other peoples experience. I’m pretty mixed on it so far and after todays 4 mile ride i’m pretty sure there is going to be a foamectomy in it’s future. But I’m going to give it more time. I learned riding saddles on road bikes that it can take time for a seat and bottom to marry into a good relationship.