Using NF tanks effectively is a sort of an Art. You need to take into account your extra size on everything. The most wonderful advantage the NF Med and Heavy have is that they both can go hull down behind a fully built wall, which adds an extra thick layer on top of the already think NF armor. The other thing to keep in mind is yes, you're less maneuverable, But you need to think in terms of how they operated the tanks the NF tanks are based off of. Stop to turn, the NF tanks will turn when stopped, and they'll do it a lot better than when moving. Be aggressive, put most of your armor on your sides and just run on through enemy infantry lines. NF tanks have more missle slots than BE Tanks, It may not bother most experienced BE tankers, but the sheer amount of missles put out by a small amount of NF heavies (or meds, for that matter) can make your average BE guy soil themselves and stay in cover a lot more. Sorry, just got the urge to spew some advice.
The endgame armor for nf, in most cases, is absorbant. Unlike reactive that be would use against missile spam its useless against anything that is not a shell. A carefull be heavy driver that puts some missiles or a dumg mg on his tank can easily rape any absorbant nf heavy.
mmh, opinions about BE double rail heavy differ. lets make a poll like "nerf BE double rail heavy?" to see what the mayority wants. what would be better, a simple poll with only yes/no or a poll with more options, like "nerf rails, buff absorbant, nerf BE heavy, buff NF heavy"?