Superb Spits -like how the Soviet hand-me-down has the TR9D radio with 'pennant' and external aerial and no IFF wires to tailplane tips, nice attention to detail and lovely skins! CFS3 has never looked better or been better equipped!
As for terrain, my preference is what comes with the CFS3 BoB add-on. There is some visible tile repetition in some areas but overall I find it very realistic and the airfields are simply outstanding!
The modified stock terrain (?) that comes with the ETO Expansion is also pretty good IMHO.