I've posted this now too many times
I would go for the Fusion Paladin L120 Pro (crap name I know...).
http://www.logicrc.com/?ItemId=O-FS-L120P&s=c:0,c:40
It can charge up to 12S at once, at up to 10A, comes with a balancer, can charge Lipos, Nixx and Pb. The maximum power is 180W, so no worries charging a 4S pack. Even when charging two 4S packs in series (8S) you should be good for around 5.5A charge rate at least 180/(4.2V * 4). (so more than needed)
It is 12V only though, but is only £125, which is far cheaper than the BC8
.