^if you want to get pull-ups, you pretty much need it recessed. I think you can pull up a little if it's not, but you need to set it up that way, and you get more pull up with a recess.
I'd imagine it's not cheap. You can get a guitar with a good floyd (as opposed to those poor quality licensed examples) for around £350 nowadays.
EDIT: by that i mean you could have two guitars for probably not that much more, when you add in the cost of routing (£?) and the cost of a good floyd (at least £130) etc., and 2>1.