I bought the original 20L bags and they were sh!t! I warrantied them through my dealer and they were replaced with the new 25L bags.
Much, much better. The have a waterproof (so the claim goes) bag on the inside with an air vent for letting the air out when closing so it would seem to be sealed. They are larger than the original. They moved the lock to the front and used better zippers. I have had no issues with the 25L panniers. They fit so well on the mounts, come off easy when necessary.
I do long (to me trips) of 6000km - 8000km for a couple/three weeks at a stretch. I am able to fill the panniers with all I need, pull one for the nights stay, and get back on the road with ease. I added the tail bag and mounted it to my luggage rack to hold things like sunglasses, a hat, sunscreen, cleaning cloths. The side bags take time to get in and out of due to the inner bag hence the use of the tail bag.
If you travel more than occasionally, I find these bags a must have. Happy to share more as and when!