Hi Ranles,
We were in LAS exactly a year ago for six nights, and O was a great show.
If you cannot arrange tickets through the hotel, go to the www.bellagio.com website as recommended above. The restricted view tickets are fine (it is front row of the second seating area, with only a stair rail restricting your view a tiny bit).

As with anything else, everyone here has probably recommended O in hundreds of other threads. It's fun to watch the clowns before the proper start of the show, so get there in time

Don't forget that other classic thread - the '$20 tip' thread - see gleff's legendary suite upgrade with 4 bathrooms!