Best ride = Old Man Emu.
Best warranty = BDS Suspension.
If you daily drive it you can't go wrong with OME - I can personally vouch for that. ARB only makes one spring for the YJ, and they do it well. OME springs and shocks are probably as close to a Cadillac ride as you'll ever get on a YJ. I highly recommend OME to anyone who wants a 2.5" lift for their YJ.
If you wheel it hard and might break/bend the springs, you can't go wrong with BDS Suspension. Unlimited lifetime, no BS warranty.
Rubicon Express also has good reviews, kit comes complete with the essentials, and isn't quite as pricey as OME or BDS suspension.
There are people who are satisfied with Rough Country, but from what I gather, the selling point of Rough Country springs for the YJ is the price, not the quality of the springs or ride.