i got one off the pressure systrem ones with the hydrotech epiment i brought,i found it very heavy to lift in out of the van also u need water pressure to fill the tank, it would be ok if u live in a soft water area as u can just connect to the custmers hose.
but i live in a hard water area and the resin lasted about 4 days , even tho hydrotech said it would last me about 6 months.
in the end i just used some of the bits added a pump and made it in to a van mount.
if i was u then go for the freedom or make your own!