Hostaway seems interesting as potentially something with the power of Ownerrez but without the challenging interface and complexity. The problem is it's by far the most expensive PMS while simultaneously being by far the least transparent as to what its capabilities and limitations are.
With Ownerrez, you can look through their entire documentation library before signing up. You can see how it works with each OTA, what limitations API has with each particular OTA, what it can and can't do, exactly, how difficult each of them are to set up, etc.
I did the Hostaway call and they wouldn't really expand on any of this. It was just salesman saying "we're a premiere partner with xxxx", etc. Well, most of those OTAs have a bunch of premiere partners and still have plenty of limitations on what exactly can be controlled via API and whatnot, so that's not really saying a lot.
Doubly worrisome is that there are almost no hands on reviews of Hostaway, and any time the name comes up on BP or Facebook groups there are suddenly a dozen new "users" whose first and only post ever is to talk about how great Hostaway is, without providing any details. Which is quite sketchy.