Doesn't BTC Guild use a 5% rate?
Anyway, as i simply fail to don understand how anything above 100% could be right... i won't use those.
Regarding 115% PPS pools, I think both Clipse and Goat are trustworthy individuals. Clipse has been around as long as I've been here and he's never done anything dodgy. But they're new pools so there'll be down time as they get up and running. If you can put up with that (using auto failback to another pool when they're down) then go for the 15% extra. Especially useful given there's bugger all proportional pools to hop anymore.
Again, this is not a 100% dedicated rig and the objective is not purely making a profit, but rather pay the bills, gather some coins and *maybe* justify getting a new card sometime.
It comes down to your nerve. Assuming an honest pool op, mining at any pool will give you the same rewards in time, minus fees. But if you can't stand the times a non PPS pool is having bad luck, go for PPS. Extras like EMC has should play a large part in your decision making as well.
The only pools I wouldn't suggest you mine at *MPPS pools and prop pools (unless you know how to pool hop) for reasons I wont get into here.