Have one on my truck, mostly positive experience but it's only been on for about a month.
Pros: Easy to fit if you can grab a spare pair of hands to hold the rails.
Has rubber seals at the front of the bed and at the tailgate.
Easy to roll/unroll (mostly, more in the cons).
Came with a free tailgate seal.
Positive lock mechanism on the passenger rear of the cover.
Low profile and actually looks pretty decent.
Tension mechanism seems to work right out of the box, no flapping at speeds up to
Rolls up very easily for bed access, also flexes enough that things that are slightly
too big to fit under a hard cover will fit (we have a cooler that is 3/4" taller than
the bed but the cover will still close over it).
Cons: Not 100% waterproof, probably 99% waterproof, you do get the occasional drip in
Sometimes the velcro sides catch as you're trying to close it, you need to walk
down each side, free the velcro, close the rear and then reseal the velcro.
Overall a positive addition to the truck, works as we wanted and protects things in the bed from most of the elements. We bought from Autoanything.com and got a great price break with a 20% discount by watching their site for a few days (their discounts vary). They are also a forum sponsor and they do have a coupon code in their section, not sure of the percent.
Hope that helps