Just downloaded the 14 days trial client. Has anyone playing this game? Is it good?

Old, but fun when I played it a few years ago. Showing its age like a fine wine.

I have only played it on a private server my friend ran, it was exceptionally fun as we didn't have to face and grind (stats could be changed to what we liked) so it was a cool RP environment.
As for the main game, I think the basic format has stood the test of time, but you really have to sink some serious hours into the game play if you want to get anywhere. Then again some seriously funny stuff can happen, and it will keep you entertained for hours.

Can a begginer player join to private servers,or it's better to use the official ones?As i see private servees using the old game client and Razor.

Stick to the official ones, once you learn a bit about the game you might want to run your own. Otherwise, to get onto a private one I think you have to be part of whatever community is hosting them.

I've been playing UO since 2004, I play on Atlantic and am currently enjoying Stygian Abyss, although I did beta test about 99% of the content for the last six or so months. :)

I play on Europa.