I'm in the same situation as you, though I'm adding PW'ing to my window cleaning business. I already have PW insurance. In researching a CW Landa, I decided to go with the MP-373534 (4GPM 3500PSI) due to improved servicability (roll cage design access to belt drive; heavy duty inlet filter) and image (more "professional" appearance.) MP is basically a heavy duty PG...
Larry Laczko
Best Cleaning and Window Service
Magalia, CA