The more I use the Bren Carrier the more I like it. I know its weak armored but self repair for 35 ammo keeps it alive and will help it escape. I use to always build LT first but now I build the BC first, right after I send the recon to cap. When the BC comes out I send it after the recon squad and qua them to get in. The BC travels about 30% faster from point to point which gives you early game capping power and helps track down kittens. I wasnt sure if the tommys was fireing from the BC so if I run into PGs I would unload fast, move tommys to cover and flank with bren. That works great against PGs, pios, volks but if you run into any HTs or scout cars all you can do is run. I tryed putting sappers with piats in the BC and sure enough they would fire from BC and reload. If you get sappers to over repair BC then it got you some fast moving AT on the field. Works great against scout cars and even HTs. Wouldnt reccomend it against a tank or AT HT. But it might get your pait carrying sappers to a spot for a ambush fast. If the BC is about to die, be ready to unload and retreat or you may loose everything.
Yes, I think the BC is very under rated.