hey everyone, I'm new to this forum, but I have been in the pressure washing business for about 5 years. For the last few years I have been using a surface cleaner that I bought from the local pressure washing store here. I think it is by BE. I got it at that time because it was all the pressure washing store sold and I did not know that there were so many options out there. After looking into it recently, I have noticed that my surface cleaner is very cheap in comparison to some of the other ones I've seen on web sites. My question is this, what is the difference? Is there a good reason to spend the extra money? Will it make me that much more productive than the surface cleaner I already have? Also, what would be an ideal sized one for a 4gpm machine. I know, I should know this stuff by now, but the guys at the pressure washer center here are always swamped, and if I try to ask questions, they start to look impatient, and give you a half ass answer as they rush you out the door. Any help would be greatly appreciated.