I liked the future as a clapped out version of now, with some cool token technology (jet bikes) and a few mutations thrown in.
The time travel bits were rather confusing - people have said here what I thought though, so I won't repeat stuff.
I was quite interested in the other Loopers, and disappointed that they weren't really major characters. And what was the relationship between the Gat-Men and the Loopers? What did the Gat-Men spend most of their time doing?