These have been in the pipeline for a while, and it is great that they are now commercially available, with more of the line on its way. I hope to convince a UK stockist to consider them.
They require soldering and some assembly. At their price they do compare fairly favourably with other Robot Kits, and in terms of electronic expandability beat the Lego RCX hands down. If you already have Lego and require a controller - I recommend looking at these first.