shoot I got an old scratched up, paint faded, getting rusty, dodge cummins diesel and I do just fine. I also have a couple signs on my trailer with my company name and number. I know of only one successful lawn company (besides Scotts or TruGreen) around here that drives around in a Post-2005 truck, and hes got a brand new silverado. Everybody around here just drives their old beat up work trucks.
If it works good mechanically, I would say run it! But thats just my area, I reckon.
My set up:
-2007 Chevy 2500hd 8.1l 4x4
-7x16 open trailer
-2011 gravely zt 52hd
-21" craftsman push mower
-Stihl trimmers, blower, edgers, chainsaws.