For me, Chambers and Gibbs are both good enough fullbacks. I had some doubts because for some reason Chambers looks awkward as fuck with the ball, but he uses it very intelligently and defensively he has recently been very good. Really not seeing him get ripped apart like some are claiming - not since Swansea anyway. Gibbs was already a solid fullback but didn't offer enough going forward. That has also started to change, seems more willing to take on the opposition RB.
We do concede a lot of goals and chances but from everywhere - middle, left, right it doesn't matter. Our shield in front of the defence is cack and we allow them to waltz through to our back line. In the last game, we nearly dropped two points when Berahino hit the bar because they had 2 on 1 on Gibbs (in the 85th fucking minute). Fullbacks need more help.