Are you marketing it like a professional listing and is the listing fully optimized with professional pictures, title, description, etc?

MartinTake a look at running a "preference test" on Verify App http://verifyapp.com/tour/preference-testI use them for the work I do A/B testing and conversion rate optimization, I'm in no way affiliated with them. 

To answer your question, I invested about 5 years ago with a group who had lots of optimism and confidence but lacked the necessary skills to properly renovate and manage a large apartment building (400-units).

For the most part, it sounds like it will take some experimenting to figure out what the optimal bid/budget price should be.

Your direct bookings site will never be able to compete with the SEO of the big players.  

They're out to optimize theirs.

@Michael Baum why not just relist after the rehabs and gain back the SEO boost for a month while grabbing better reviews?

Make sure a deal is sound as a LTR and then optimize via STR if needed, but the STR path to quick money is gone. 

Are your current rentals optimal for STR?

We are locking in good debt and chasing deals where we can get optimal financing.