Pros: Already assembled, well-made, sturdy, lots of play space with small foot print.
Cons: Already assembled, may have delivery issues, price varies wildly.
This tree is nice because it provides a lot of play space with only a 2'x2' footprint. It is 6" shy of our ceiling though so if the kitties are on top they can't stand up all the way. We put it next to a row of bookshelves so it is like their ladder access to the top of the shelves. It is very heavy and does move slightly when they get a a running start and go flying up it (especially the 16lb Mr. Tubbs). Our little girl cat likes to lay on top almost every night to monitor her minions below. She also likes to look out the nearby window from high up during the day. The sisal scratcher is plenty high and used mostly by the very tall Mr. Tubbs. It has held up pretty well for over a year and I just clip off some of the plastic threads from the clawed at carpet parts occasionally. We got the taupe colored tree which blends in pretty well with most neutral colored rooms.
Pre-assembly is both a pro and con. You don't have to assemble it... but you do have to figure out how to get it in the house and maneuvered into place. It is very big and heavy, measure well before ordering. It came by freight delivery services, not UPS or FedEx. I was informed by the driver that they are only allowed to leave it down by the street, and that most people aren't aware of that (he said with a very annoyed look). He was nice enough to help me get it up the driveway and pushed in the front door though. Plan to have some muscle and or a good-sized dolly on delivery day. I doubt anyone would steal it from your yard... due to the size! But, it comes just in a plain cardboard box that gets pretty beat up, no plastic. If left out in the rain or snow it would get nasty pretty quick.