Gerald,
It's nicer than what I have. I am still using cold water. I hope to get a hot water system some time this season or by the start of next season. For comparison, Bob's comparable unit
http://www.pressuretek.com/8gpm35psihot.html is $5,555 (US). I just bought a 16' trailer brand new for $1400. That would leave you $2500 to buy a water tank, some hoses, and reels to make your own unit. I think you could spec out your own, save a little money, and have a better unit. That being said, it doesn't seem like a bad deal, just not a great deal.
Also, that 12' trailer looks pretty full without any chemicals or a surface cleaner on board. Unless you are wanting to take those things in and out of your truck all the time. I think Iwould at least get their 14' for the extra $400 if you are set on going that direction.