I hit lvl 50 on my vanguard a couple of days ago and now its feeling good after being a bit iffy in the earlier levels. Mainly ive had trouble putting out decent DPS even after trying a few different builds.
Now im full on tank and have been playing quite allot of pvp with a couple of other players in my guild. Both are level 50 Consulars, one DPS spec and one Healing. Between the 3 of us we can own pretty much anything. If you put your guard on a good healer, stay with them and play your class well you can cope with ALLOT.
A few times now myself and the healer have held off 4-6 enemies for minutes at a time. Even before i hit lvl50. If you work well together you are really hard to put down in pvp. Add the 300-400k damage per match from Consular 1 to the 300-400k Healing from Consular 2 to the vanguards protection and your on to a winner.
I get top medals pretty much every game of PVP even if i lose tho 10 is my record so far.
As for 1on1's in pvp you can pretty much take on anything as long as it doesnt self heal I quite often find that i cant put out enough DPS to counter the heals and have to drag the fight on untill my stun CD's finish. Either that or just give up/call in backup.