Hi Matthew,
We have 7 Air BnB's and have both the August Smart Locks with the August Connect and Keypads as well as the Schalge Connect with a Smart Things Hub.
If you want simplicity in setup then August is the way to go. Their products have come a long way since I first started using them where they would constantly stop working. They are now much more reliable, however, the batteries on them need changing every couple of months.
The Shclage Connects are much more to my liking as they are also rock solid, the keypad is built in and the batteries last about a year.
They are also much cheaper than the August as it comes with a deadbolt (August uses your existing one) and as mentioned above, has the keypad built in. (August requires the keypad and a Connect unit).
They both now have the ability to integrate with Air BnB, although the August integration doesn't give you any options in how to set it up. I am using a third party app on SmartThigns called Rental Lock Automater (RLA) which I love.
I've tailored it to automate the entire process. It creates users with codes that are the last 4 digits of their phone number for the period of their stay and text the guests a template which you can customize with form fields. So all their checkin instructions can be sent automatically without you needing to do anything.
After the guest has checked out, the user is automatically removed. With August, the users all remain in the app and you have to delete them manually. As well, You cannot modify the automated email August sends the guest.
If you have more than one lock, then the RLA can also set the code for all the locks to be the same for the guests stay. I prefer this from a guests perspective as I don't want my guests to have to remember different codes for different doors and this is the case for August. August also provides them with a 6 digit code which is overkill IMHO.
The RLA will also integrate with other platforms so if you're hosting on multiple platforms, the integration is already there.
The only downside to Smartthings and RLA is the setup. It's a to do to get everything setup and will take a few hours of learning the Smarthings system, following FAQ's and setting up new accounts.
For me, it was absolutely worth it as the few hours I spent initially, have saved me hundreds of hours creating users and codes and communicating those to guests.
So in summary, August is higher price but very easy limited integration and poor battery life, while Schlage is lower price (40% lower), more difficult to setup but provides lots more options and features and batteries last a year.
Good luck!