Purchased a JetWet portable washer just before Christmas, before the sale 🙁. Used it three times for cleaning my cyclocross bike after one long monster cross ride and two CX races and I am really pleased with the washer. Basically it has just enough pressure and flow, and water capacity to do a great job and means the bike goes back in the car clean.
Battery is fine, haven't run it to flat yet. Nozzle works well and is not a crapy plastic affair. Overall quality is very good. The Bikerader review said it felt a little homegrown and that storage could be better – can't say I agree, I think the whole package works really well. Definitely recommend if you ride in the mud, saves me a lot of time trying to clean off dried on mud when I get home.