I've had both kinds.
Real trees smell and look beautiful but they go brown and droopy too quickly, they make a mess and I just feel bad when it comes to throwing a young tree that might have lived 100 years on a tip for the sake of a couple of weeks festivity.
Fake trees make less mess and can be reused time after time, but they don't look or smell as good and I'm dubious as to whether all that plastic is really more environmentally friendly than throwing away a live tree.
Which do you have and why?