I just got the roller classics for a good deal from a local bike shop. I happened to a buy a surly too.

They seem robust and cling to the rack well. I don't have much time with them to comment in depth, but I do have quite a bit of experience with camping equipment, design, material, etc....

I don't see any reason (barring some kind of bear or squirrel attack) why they wouldn't last a long, long time.

I have no problem with one large pouch. I can organize my travel equipment well enough. If I had a pannier with multiple pockets, I would just end up forgetting what was where.
Hell, I lasted 5 months on the AT with a simple rucksack.......