@Amanda Williams Congratulations on your pending purchase.
I started running my STR last March, but here's my experience, in case it helps.
I started by listing on Airbnb only, for a few reasons. They are the most 'known' platform for Short Term Rental. I wanted to aggregate all my reviews in one place, to get Superhost as quickly as possible. I didn't want to try to learn and manage multiple sites while learning what I was doing simultaneously.
I did eventually add HomeAway (sister/same company now as VRBO). They were a bit of a nightmare, and I pulled my home from their site after they effectively stole money from me (long story).
I tried, and ended up using and paying for beyondpricing.com to manage my pricing. They have full time staff evaluating the competition, vacancies in hotels, events, etc. For the minimal amount I paid them, I felt they returned much more to me in higher rates than I would have charged, and especially for the time it saved me from dealing with pricing. They will manage Airbnb and HomeAway/VRBO directly, and keep your bookings synchronized between those 2 sites automatically.
My research showed that HA/VRBO is generally the preferred platform for full home rental, families, long stays. Airbnb is considered better for short stays, singles, getaway travelers.
My home was definitely in the VRBO camp based on the above, but I did great with Airbnb, so I don't think those 'rules' are set in stone. I mostly had families, and usually 3-7 day stays.
I agree with others that you don't really need other software for your first one, and doing it yourself lets you fully appreciate all that needs to happen to give guests a great experience. I'm very happy I did it myself and learned what i did.
Eventually, I tried a property manager, and it was a terrible experience. I fired them after they showed their incompetence and never earned a booking for me.
I think much of the difficulty was that I had high expectations from my experience running it. If I had never done it myself, I might not have been so unhappy with them.
Eventually, I got tired of cleaning the place myself, and values in the area (very rural Weaverville) have gotten so high, so I listed it for much more than I thought I could just 6 months earlier, and sold it quickly.
I'm using that money to finish the rehab of another property now, and am seriously considering hiring a different property manager to start the listing and do it all from the beginning, to avoid the 'take over the listing' issues I had last time.
If I can help with anything, or answer any questions, please let me know.
Good luck with your new asset!