I've never found a handheld blower that can blow wet grass effectively.
Seriously though, if you're getting paid to do what you're doing, then time is money my friend...
What's the difference between a $300 home depot lawn mower and $1000 exmark 21-22" lawn mowers? They both will cut about the same and use the same amount of TIME to cut. Main difference between the two is that one may last a season at best, while the exmark will last easily 3-5 years with good maintenance with commercial use.
OTOH, a cheap handheld/backpack blower will SLOW you down, while a good one will speed you up. The Stihl BR350 mentioned above is 'decent', but I'd spend the extra $100 or so and get a Husky 570BTS with 770 CFM and 236 MPH. That sucker will move rocks and bricks! It's the current hot seller amongst commercial users. I've been able to get a few ebay sellers down to $425-$450 range. I personally use a Stihl BR600 and it's still kicking strong after 5 years, but I do have to do valve adjustments that the Husky won't need...
As they say buy expensive - cry once, buy cheap and cry twice...