Not too good, mine is an old model though. The newer ones might do better. My cat doesn't shed much but it fills up quick.

I have one in my bird room and it does really well with just seeds, feathers, pieces of veges & fruit. I clean the bin every other day and check the brushes about once a week.

The dog and cat hair in the rest of the house is another story. I ran my Roombas for a few months then I upgraded them with a CHM Mod by Vic. The link below will explain why I did this. Vic now has a web site but I came across his work on this site: http://www.robotreviews.com/ Check out their Chat Forum for more info than you ever wanted to know about Roomba!

I can now tell by the sound of my Roomba when I need to check it and clean the hair from the ends of the brush and bar. If you don't it will eventually shut down and can actually damage the plastic parts of the CHM (cleaning head module). If I've let a few days go by between running the Roomba, and it's my dog's shedding season, then it's not uncommon for it to need cleaning half way thru the cycle. Otherwise, if I run it daily, it can run the full cycle without me checking it.

So, yes, you will have to clean it every time it runs if you have dogs and cats. But even with that, I still find having the Roomba frees up my time to do other things beside dragging out the vacuum. Cleaning the bushes and emptying the bin takes me less than 5 min.
If your house is large, you may want to consider two Roombas.......one for the bird area and one for the rest of the house.

Here is a link that might be useful: replacing ball bearings

Hair: Good
Poop: Bad

Lol weed........Horrors indeed! And I thought it was pretty bad when I discovered my Roomba had caught and killed a mouse!

My bird room is connected to our shop and during the hottest days of summer I will leave their door ajar for some of the cool air in the shop. Apparently a mouse had found its way in and probably thought it had found a neat little hiding spot inside Roomba, until it started running on schedule the next morning!