Put the Pecos bundle on my WR250R for the Idaho BDR, along with some Mondo straps to hold a rear top bag. Pretty hard to beat the value of this bundle with anything else on the market for the amount of storage you get. The bags held tight to the bike for the whole trip and on 1 day where they shifted a bit the stretchy straps took up the slack. Side bags were 16 lbs (exhaust side) and 19 lbs fully loaded right before I set out. Top bag held w/ mondo straps was about 12 lbs. On some days I would strap my backpack, jacket and armadillo bag with extra fuel on top with the mondo straps.
The biggest pro and also biggest con of the system is the flexibility. You can strap anything onto your bike (within reason), and that coupled with the price was why I bought it over other options. That can be a con, where you spend a little time on initial setup and occasionally in camp reconfiguring straps, but after the 2nd day on the BDR I had things figured out. If you don't mind having to think about your setup a little initially then this is a great setup.
I did add an extra D ring to each side to act as a bottom strap on the bag so it wouldn't slide down. Probably unnecessary, and was the only strap that shifted off the bag during the BDR and the stretchy straps took up that slack when it slipped off so I had no problems with the bags moving.
Laid the bike on it's side a couple times and the bags held up great. The only real wear was on the exhaust side bag where it rubbed against the heat shield.