I prefer the B, but I feel bad about using them in pick-up matches. The most effective behaviors with the mech, namely picking away at your foe at top speed while maintaining range, it's not a particularly FAST technique, nor is it the most fun to fight against. Thus I prefer doing it in games against the bot, or against an OpFor who is playing with the full knowlege that the fight isn't intended to be 'fair'. I've also adopted the position of using the Stealth Armor only as an out-of-combat feature, i.e. while advancing to the fight, scouting, or retreating from a threat the wulfen is inappropriate to face.
It also helps that I am a BIG fan of certain optional rules like Extreme Range, Kinder MASC/SC, and MaxTech Move Charts. In vanilla TW, I expect it would be a little less amazing.
It's not my first choice for a clanlike fight. It is however, useful, on the ever-unclanlike battlefields of the inner sphere. Bottom like, if you want a stand-up fight, give me a moment to requisition an adder. if you refuse my batchall, well, here comes the Wulfen to sniff you out and snipe at you.
But, even more than the questionable choice of pairing an XXL heat hog with Stealth Armor, what bothers me about the Wulfen is that the old fluff prior to the release of the wulfen indicated that it was built to partner with the warwolf, and that seems to have fallen by the wayside. Likely because it's damn hard to incorporate a NARC onto that mech the way MWDA had it