Is OnSightPROS.com a worthwhile service?

[Andrew S.]

This is a company that will perform scheduled inspections of your rental property to identify deferred maintenance needs, dubious tenant activities (say, illegal pets, bad housekeeping, failure to change HVAC filters etc).  The reports are fairly extensive with pictures documenting various items.  Cost is $150 and up for each report.  Is this worth the cost?  Should it be done more than once a year?  Is this something a PM company should do anyway?  Just looking for general feedback - I expect opinions will probably diverge on this....