I've heard mixed reviews about the BL-2s. Don't need anything overpowered, but I do think having something responsive/intuitive will make for a much smoother learning experience. I would be inclined to get the XL-5 since they are cheaper, and then throw in a cheap HW system down the road. But if the BL-2s provides a decent driving experience, that is probably cheaper in the long run.
I race the titan brushed motors for carpet spec slash, and they seem to hold up ok there. But I can seem them failing early and often if used outdoors.