Although I don't have the Spin Wash, I do have a cheaper alternative to the Nitty Gritty machine that works as well, but you need your own canaster vacuum. The KAB EV-1 is all manual, but works on the same principals as the Nitty Gritty: http://www.kabusa.com/frameset.htm?/
It's a steal at $159. Been using it for several years to clean filthy, used LPs I get at shows and thrift stores with excellent results.
Would adding the Spin Wash produce even better results? Probably, but I am too cheap and lazy to bother.