Widger,
I say it because it's still dead mans shoes when it comes to promotion above 2 and a half; and even then a lot depends if you happen to be in the right place at the right time and fit in with the appointing cycle.
Hence why I made the comment in direct reply to the idea of 'career' which is what Bex mentioned. If you consider career not to include promotion prospects, then fair enough!
However on the flip side, I would say that the variety of jobs as an ATCO in the RN is better than in the RAF - they (Crabs) have a lot more bases, but not the diversity.
You are correct, retention is not a major issue, but how much of that is to do with job/pension security and the 'fear' of letting go of that safety net, as opposed to how good the 'career' is?