Hey rocketred,
there's nothing wrong with the addon, if you can get it at the right price. I would install it as a stand-alone though, and only really for curiosity value. its got a two-bladed hurricane and a number of other oddities, like a hurri with rocket loadouts IIRC. Its also got a different but dated set of scenery textures, and some different airfield facilities like camo hangars.
I'd install it just for the missions, but I'd also add a lot of BoB era aircraft.
the thing is though, PatPs BoB add-on is the same thing on steroids. the ETO-like aircraft, the v 4 flight model of Pat's aircraft, and the lovely pits for the spit, hurri and emils mean that Pat's addon is like a more sophisticated, new generation version of the JF BoB addon. I just like to have the JF one as a bit of a "quaint" older version. Also IIRC Charlie's 1940 seems to go well with the JF aircraft because his spawns often called for the JF aircraft.
If you are a confident tinkerer there's lots to like about the old JF Bob, but flying in Pats version straight after is a whole new ballgame.
HTH,
D