I have a cheap Bell catalyst 300 ulock from WalMart.

How good are these?

I also have a smaller Kryptonite which seems pretty solid and has the bent foot design. Problem is that the Kryptonite doesn't fit with some bike racks.

Should I just cough up some money and spring for a better ulock that can fit around all bike racks?

Also are folding locks any good? I hate the size of u locks.