I do have a bunch of the Toontrack stuff, I bought one of those six packs already, I am just getting a feel for what else is out there.
I have just had a play around with the demos from Piano Loop and they are pretty good and different from the Toontrack ones of a similar genre, certainly worth downloading as you get a reasonable amount of patterns for a free demo, and there is a demo fro each pack. Nothing on my "to buy" list for the time being.
The loops are in MIDI format, not Toontracks propriatory format so you get the import options dialog when you drag them in from the browser. (the same as if you drag in a track from your DAW).
It also looks like it is going to be pretty easy to use and organise my own loops using the folder templates from the Piano Loops stuff.