I am on my fourth Roomba in less than 4 months. This last one didn't last a day and it won't charge. I am sending it back this week after waiting two weeks to get a replacement.  The people on the technical support line are just reading from a script that they have in front of them.

I have two rommba's and two charging bases. My 4150 model works just fine. I really do love the product when it work it works great. I just wonder how long it will last after the warranty is up.      

I have three of the Roomba Discoveries, for over three years now, and they are still working fine, and are well used.  I've only had to get new batteries for them ONCE so far.  This is the main reason I am so hip on the Create, because the Roomba's seemed to be well-built for Use and AbUse.  So far the Create's only recurring problem is dirty wheel encoders causing loopy results sometimes. (this doesn't seem to be a problem with Roomba's though)

Oh, one broke once because my kid dropped it down the stairs.  So much for cliff-sensors    But I had the super-warranty (from Sharper Image) and they replaced it without a problem (I don't think they knew How it broke, I appreciated their don't ask, don't tell policy).

Since so many people seem to have to return them, and iRobot doesn't seem very quick-to-respond regarding tech support, I'd suggest purchasing it from a local retailer for faster returns/replacements.  Purchase the extra no-hassle warranty, at least for the first year, if it lasts longer than 1 year, then it'll probably survive the next few as well.

Purchase extra batteries and docking stations online from amazon or something, they seem to have better prices then anywhere else.

Make your own Virtual Walls... http://irobotcreate.googlepages.com/createanirbeacon