Hi!
I have been riding Ortliebs for 10 years, I know friends of mine who have been using them for over 15 years..and everyday on their way to work, shopping groceries as well as vacation. None of them have any problems.
There are other good waterproof bags BUT Ortlieb was the first (one of the first) companies to introduce waterproof gear, they carry all of the parts as spare parts even of older/very old bags, and they are very nice about repair and/or maintenance. A friend of mine sent her 12 year old bags to change the carry system to newer QuickLock1 and it cost her 5 Euros! Another friend sent her 10 year old frontrollers and they repaired the holes from an accident for free.
I think they are difinitely worht the money!
I would suggest to take the backrollers, you can also use them as waterproof clothes bag for canoeing.
Nadine.