I have seen a bit of both and as far as I can see
In the RAF you can get away with just wanting to fly and still have a chance of a decent length flying career whilst still being well thought of (if you are any good and a nice guy) also you can stay in as spec Aircrew - doesn’t mean you wont be stuck with a ground job you don’t like but complaining about it is a little more accepted.
However if you want to do a few years flying and then move about a bit either into interesting roles within the military or to something else out side with the option of coming back into some specialist jobs relating to flying or being the Aviation specialist working with other parts of the Navy (or any part of the Defense sector) and you find you like ships and going to sea then FAA is the way ahead. You can also get to work in much smaller units - you may be the only Aircrew on the ship in some roles.
So go and look at both, find out if you like ships and recon you would like going to sea, then think about whether it would bother you to spend all your time in the South West (Yeovilton or Culdrose is the option these days)
Good luck what ever you choose and keep both options open for as long as possible