I am using property management for most of the rehab and have a backup source for specialty/smaller works. PM specialized in rental property rehab for OOSI. Between PMs, they charge pretty much the same rate; however, they maybe vastly different in quality and/or how fast/good it can be done (or how busy they are at the moment). You just have to spend some time on the phone or email with them to find out their services and your level of expectation/budget. For example, the window covering itself, material only. PM will install the cheapest version 1" pvc ($200), a Sub-contractor you hired may install the 2" white faux wood ($500), You, on the other hand, may desire or expect a 2" real wood ($1K). Labor cost I found doesn't deviate much. They really earned their pay.
good luck !