I have had drinks and watched WoC from the Cove Bar. If it is your first time seeing WoC I would not recommend it for the view. As you can see from the pics above, you get a nice view of the fountains, but your not going to be able to see much of anything clearly on the water screens, at least the front one.
I don't recall if we were charged a cover, I don't believe so. It was a slower night and tables in the Cove remained open. Be aware though, twice they have said we have to be in the bar before like 7(?) for the 8:xx show. After that they were not letting people in. I have found service to be a bit on the slow side, but it is nice to kick back, enjoy a drink and snack on something when there is no other evening entertainment at DLR.