I bought WOP a few years back - actually, to be strictly accurate, I bought the Powerpack which bundled "Wings of Power - Heavy Bombers and Jets" with Firepower for CFS3.
Do I still use it? Yes, there are some very nice aircraft in the pack. Would I pay 70 bucks for it? No, but a quick look on
Amazon shows it can be picked up for less.
As I said, there are some very nice aircraft in the pack and, in a couple of cases, they are the only game in town; as an aficionado of German jets this is the only way to pick up an Arado 234 (in any sim - Milton, if you're looking for a future interesting project .....

) and the Ta 183 Huckebein is much better than the only freeware alternative out there. In terms of the heavies, it's variable; the Lanc, B-17 & B-29 are ok but there are freeware alternatives that are about as good, if not better (Dave Garwood, the FDG/ex-SOH Donationware and Gnoopey's, respectively) but I don't know of freeware alternatives for the Liberator & Privateer - in short all the models are good, if a little dated, and in a couple of cases this is the only game in town.
Possibly too much info there, but I hope it helps.