The only improvement I can think of would be to allow a more advanced login - instead of having to enter my password into the front end - use the OTP as the authenticating factor.
Otherwise, a good increase in security as far as I am concerned.
I have gone to the author several times during my support subscription and have been blown away by the super quick response time. Never a problem getting an answer and never an issue with their customer service.
My clients have been very well pleased with the software as well. From the front end, your client will be able to add/edit listings just about the same as from the back end so you don't have worry about them going into the back end unless they need to.
There quite a few extensions that can be installed with this which make it a real asset. If you are concerned with sending $$ for support, it will be very worth it. Due to my limited client budget, I could only do 1 month of support, but it has paid for itself more than once.