I've been really impressed by this computer- I bought it a few months ago and it's quick and efficient and it was very reasonably priced. My only gripe would be that I had to buy speakers even though the customer service people said I wouldn't. I'd definitely recommend it.
Just bought one of these systems as it appeared to be a very good buy for a complete system. It uses an Athlon II 170u single core processor which is an AM3 socket processor, initially this looked good as it would mean upgrading to faster processors in the future would be possible. Unfortunately the manufacturers have used a custom unbranded motherboard with an old AM2 socket on it with a custom fan. Therefore trying to utilise the newer processors is not possible nor the use of the processor fans supplied by AMD, so be warned. It also appears to use the older DDR2 memory and the system case is so small that half sized cards will need to be used if the graphics are to be upgraded or any other cards are added.
It is a very basic but cute looking system but with very limited upgrade potential and the lower rating has been given due to the use of the old technology inside. It is actually branded by Emachines and unsupported by Acer, but Emachines technical support have limited information about the model.
Windows 7 appears to run OK prior to the installation of any AV or other security software.
We have managed to get an Athlon II X3 455 to run in the system which has definately speeded it up but the processor runs hot due to the naff custom fan which is supplied.