I've also had personal experience working for DPI -- and it was awful. They lied, shorted me on pay, and paid more than a month late.
Several of the other contract captains at that location told me that they had been treated rudely by DPI (this was apparently accepted as the norm), but they WERE paid correctly and on time. I have only heard directly from one other pilot acquaintence who says he was cheated by DPI. So... your mileage may vary.
I really enjoyed the job and the location, but working with DPI was truly miserable. I now ignore all DPI job ads and emails... their Head of Sales and the account manager were blatantly dishonest, so I simply won't work for them again. Plenty of other jobs available.
My advice... AVOID DPI if at all possible. If not possible, get EVERYTHING that is important to you IN WRITING. DPI tried to cheat me out of even more than what I had already been shorted... I had to repeatedly INSIST on being paid what was already in writing.