I do like the Oxebar system as a low-cost solution, They work great most of the time. Great format and footprint, just need to be a little careful on concrete, and when cleaning that you don't flip a full one to dump(the vacuum will collapse it pretty quick). I can't wait to order some of the 4L ones.
I do see in the picture, that you thread-taped the connectors..Did that help get a better seal? Did you also tread-tape the keg? I have had issues getting the seal "just right", I didn't think of tread tape because I thought they had rubber gaskets, though now I'm going to have to check again.
Also, is there a recommended brand of ball-lock connectors with these? I've had hit or miss success, sometimes I have to hold the ball-lock connector down to get beer or gas to flow. I have mostly CMBecker, though I'm sure there may be cheapies in there too.