This may be late, but since we have a Nitro Wall Climber and the topic was active, I'll chime in here. We bought a factory refurbished Nitro (for about $350) when we installed our pool in the beginning of Jan 2011 and absolutely love it. Not only did it vaccum most of the debris that the net couldn't get from the initial installaion (rocks, dirt, metal screws, small chunks of concrete from the coping & deck pour, etc), but it also gets a lot of the pollen that is now showing up in our water. The bag is not mesh, but rather a really close weave fabric and it's pretty sturdy. Also, the bag is too easy to clean and it is quite large. We really like that we don't have to run the pump to clean the pool (cheaper operation that way), and the debris that Nitro gets does not end up in our filter system. We did have a warranty issue after the first few weeks. Basically our Nitro just stopped working. We followed the troubleshooting steps and then called Smart Pool for help. They had us send it to a service center in Louisana. Even though we bought a refurb, they paid the return shipping. Our Nitro was totally covered under warranty and we had it back working cleaning our pool in about 10 days. So far no issues and it's working as advertised. It climbs the walls and works the deep and shallow ends of the pool well. So far we've only had it get hung up on the drain only a couple of times. We think that having the pool pump on a higher speed may have kept it stuck there. Oh, and if you check the Smart Pool site, they sell every part of the Nitro piece by piece so you can repair/replace anything if necessary. Additionally, all you need to disassemble and reassemble the Nitro is a phillips screwdriver and they also have videos that you can download that show you how to replace all of the parts. We've only had our Nitro in operation for about 2 months, but so far we are very happy with the product and the service we've experienced from Smart Pool. hope this helps.