I use the B variant almost exclusively. The range and burst damage of the CERMBLs allows sniping as well as limited AA, while the SSRM4 increases short-range DPS and reduces return fire slightly with screenshaking (assuming it doesn't glitch). The burst nature of its weapons also allows it time to watch where its going between shots.
Every time I've seen or been in a heph, everyone aims for the turret, including me. It's not really any harder to hit than the hull is, and in some cases is easier.
By the way, does the C variant have an incorrect menu description? It says it has 1 CERMBL 1 CERSBL, but unless I'm mistaken it actually has 2 CERSBL. Never bought it myself, but I've seen others use it and noticed a distinct lack of green lasers.