Yes. For every goal in a match such as AV, you will get a substantial amount of experience (usually equal to a quest hand in for your level bracket. So for killing Galv/Belinda or for destroying a tower/bunker, you will get 16,000xp)

Also, in games such as EoTS and AB, you will gain the same amount of experience mentioned above for every 300 resources or so. So even if your team loses 1600-1500, you will still gain a fair sum of exp, before your bonus for it being a BG weekend or a random BG.

I find the 40 man BGs the best personally. Mainly because I can either tank a mini boss or hold a tower/bunker by myself and the rest of your team really appreciates this.

You will get A LOT of abuse if you are boxing in a 10/15 man bracket and your team loses, mainly for lack of anyone else to finger the blame at. Don't be discouraged though, just turn off your BG chat