Its a tough one. Many on this forum over the past few years have indicated that OATS is the place to go, and as many (if not more) say the OATS does not do anything for you. I read a topic a few months ago, and some airline bod said it did make some sort of difference.
But, when no-one, or very few are hiring, what difference will it really make? My gut feel is that if i could afford it, I would go. I would add though, to not spend all your dosh on Oxford. Budget that you might have to invest 20K to do a 737 rating to get into Ryanair, or Easy Jet, and then see if you can still afford it. Do not rely on OATS saying that 'airlines will be calling you'.
Off topic, the APP seems bleedin expensive. I would prefer just the straight integrated course which they don't seem to do anylonger.