I find the thumby F gets easier the further up the neck you go, till the 9th fret or so.

Learning to do an F barre is excellent practice, and strengthens you and all that, and is really handy playing in certain keys. But a thumby F has so many conveniences (eg changing from an F to a C in a hurry and back) that it shouldn't be seen as a cheat's way out of doing a barre F. You really do need to have it available.