I have the rear waterproof panniers. They look like are a larger version of the front waterproof pannier, so I would guess that they have the same rack attachment.
The pannier is waterproof and roomy. No complaints there, although the material seems a bit thin so I'd be careful about packing anything with sharp corners (I haven't had any punctures after a year of commuting).
However, the construction & rack attachments SUCK. There are 2 flat rubber-coated metal hooks that hook onto the rack. A 2-pronged metal hook on an elastic band hooks onto the bottom of the rack. If this starts to stretch out, there are buckles you can use to re-tension the elastic. There are 2 velcro straps sewn onto the top of the bag that can be wrapped around the rack for extra security. On my bags, the velcro straps are not spaced out evenly, allowing me to fit the straps around the rails on one side of the rack, but not on the other.
Also, the hooks are attached by rivets. I normally commute with a notebook, change of clothes, spare tube, mini-pump, patch kit, tire levers, and my lunch. Nothing terribly heavy. The rivets broke, leaving the hooks dangling from the bag...unusable. I drilled out all of the remaining rivets and replaced them with nuts & bolts, reattching the hook. Now it is secure.
Also, the webbed handle is sewn onto the bag's cover, not the bag itself. The cover is attached to the bag with 3 rivets. When you lift the loaded bag by the handle, all of the bag's weight will be placed on the rivets attaching the cover to the bag. Replace these rivets with bolts as well. My cover broke off before I swapped the rivets with bolts. Now that I have bolts, it is much stronger.
I do not recommend buying these bags unless you plan to upgrade the rivets to bolts. Then it will be worth it if you are on a tight budget. I bought all the nuts, bolts, & washers I needed for $2.
Otherwise, just fork out the dough for a good bag.