OBA mixed reports
I have no axe to grind about OBA but a good mate of mine used them and had no trouble, what he did observe was a bunch of guys acting like a course at OBA was some sort of holiday and wondering why they did not get finnished on time.
What I would say is look very hard at the USA option with a view to ALL your expences I think that you will find that with the £/$ exchange rate flying in the USA is not now the best overall option (but I would say that!!!)