Pretty good. I've got the Biomaster XTA and its very easy to set up and use. The instructions say to re-set the clutch and spool system from scratch at the beginning of each session but I don't find/see the need and in any case it is a few seconds from start to finish.
Presumably it works as well if not better in the higher spec models so I'd give it a thumbs up for ease of use.
If you have big hands/fingers you might find the clutch adjustment somewhat small and fiddly but otherwise its a quality piece of kit.
