Not a good one. It CAN be done, but it requires a lot of finish touchup, and is quite expensive if you have it done. It is also pretty tough to get a good job if you haven't done it before. If you really want to go that way, it is much cheaper (and probably better) to just buy a different body.
As to the "is it better" question, no neither one is better. They ARE quite different, but which one you like is a personal thing. Look at the Clapton Strat; it comes standard with a blocked trem, because he doesn't use it, but he prefers the sound of a trem to a hardtail. If you like the way it plays and sounds right now, why change it?
The only reason mine is a hardtail is because dad wouldn't let me build one with a trem when I was thirteen, partially because he didn't want to pay for it I'm sure, but also because he didn't want me fussing around with that when I needed to be practicing scales and shit. If I were to make one today, I would probably go with a hardtail, but only because I don't really ever use the trem on my "super-strat" (figured maple top, Schaller Floyd copy, Sperzels, and a Seymour Jazz/JB combo). Of course, it could well be because I rarely play that guitar at all. Who knows.
Light
"Cowards can never be moral."
M.K. Gandhi