I bought it few months ago, I think it's underrated solid simulation, good revamp of an old gem (Rowan's BoB). However, there are few issues that bothers me:
Strategy -Like kesegy pointed out, I'd prefer "simple" pilot's point of view, squadrons and resource managing through all the windows is still hard and confusing thing (have been flying Mig Alley since 2000)
Graphics are very good minding the core engine years, apart those multiple layered top clouds, which tends to disappear on my ATI (newer GeForce works ok)
It's really, really hard one on full realism, first few missions I wasn't even able to pursuit and intercept bombers
Some objects (ships) are straigh from original BOB, may change with patch
In fact it's stable from 2.05 up (currently playing 2.06).
And things that shine and makes it worth buying:
AI!
Pits -have that good old EAW feel, good detail and performance
Dogfights -it's best at portraying WW2 furballs, had Pacific Fighters for a short period of time, that battles compared to BoB 2 are tiny
Radio and ground control -declaring emergencies, leader calls ("That's it! Shoot him!"), many many excellent voices
Clouds and lighting are nice, aswell as that watershader
Developers seem to include best from user made content into it, as seems by the 2.08 preview
This topic makes me wanna launch it this evening
And I look forward to their new upcoming title focusing on Burma and P-40 + a new terrain engine
Post Scriptum:
Don't know if you are aware but there is an action sim called "Air Battles: Sky Defenders" which is in fact BoB 2 without campaign (only BoB 2 customizable instant action missions), switchable action-style HUD display and different terrain textures, plus few others tweaks, have it too.