Reading old posts, the consensus seemed to be the AD route was the most competitive... I'm not sure that's still true, the number of folks accepted has increased from 14 a few years ago to around 90ish i think this year.
But having gone from enlisted, to non-rated O, to UPT select as a new Capt, I'll say it's a long road and you'll be behind your peers and making rank past O-5 will be a challenge. I don't mind and have 0 desire to make O-6 or higher, I just want to fly and do cool shit... but for some people that might cause some butt hurt.
My advise would be to get a UPT slot out of the gate if able, but there are roads to wings if you can at least get commissioned.