Jon, excellent summary of some common issues with managers of single family properties.
RL Property Management Group in Columbus, OH addresses your complaints in the following way:
Insufficient value provided. - We do not charge leasing fees, as it sets up the bad incentives you describe. We want to be managing your single family property in 10, 20, 30+ years. We desire the best residents for this reason. Great residents benefit the owner and the manager in the long term.
Padding contractor charges. - We pass on contractor quotes as we receive them for owner review. We do however charge a small markup on these quotes if we manage the completion of the job. This markup is outlined in our Property Management Agreement, and covers the cost of our time.
Poor service quality. - We only do property management. Our employees and owners do nothing else. We have seen the issues you describe (when agents do "part-time" management) in our area. Common response from residents renting from our company is "Wow, you actually take care of maintenance issues".
Managing single family properties has a whole host of challenges. The solution to what many consider a "million dollar question" is being worked out by the few good property management companies out there that you describe.
Adam Rich
RL Property Management Group