I really like the changes with i0coin, faster target block solve time, wallet encryption, etc.  But I'm a little concerned that it will still suffer from difficulty yoyo-ing like namecoin does.  I know it's set that it adjusts every 7 days in addition to after a certain number of blocks, but I don't think that will solve the problem.  The biggest problem is that as far as I know the blockchain can still only adjust up or down 4x (or 1/4x) per adjustment. So if after the fad wears off 95% of miners give up, it will still take 3 weeks for the difficulty to adjust to where it should be.