I have been using Listify as a Theme for approx. a year now and have a pretty good view of what it delivers. In line with what most say, the code is good and clean, documentation is weak, and you will need a lot of other plugins to build a useful platform. Support is typically quite helpful (thanks to John!).
However, with the recent version, there are some problems that don't seem to get fixed and I had already flagged to support, who passed it on to their developers. This relates to the map on a listing shown on the sidebar (even if you don't place it there) and to the fact that it seems that user avatars have been removed and there is only a consolidated option for company logos (something that used to be separate before). This isn't shown on their demo version, as it still uses their old version. I have to say I find it quite troublesome that there are invasive changes to the Theme and you are not notified in advance and neither is this covered in the changelog, it's like letting your customers run over glass and hope for the best. So you find your page suddenly not working properly anymore, which is frustrating at least. I have also followed up and understand that developers haven't fixed this yet. I also found an issue that when you make a selection on the start page and search, amend the service in the drop down service on the search result page and go back in the browser, search again, then the 2 dropdowns start conflicting with each other, showing different values - I had to hire a developer to fix this. In the end, I would have rather paid twice the price and have a more professional theme that you can trust & rely on. If it wasn't for the code quality and John's support, I'd rate this less. If you buy this Theme, make sure you budget in additional plugins and hiring a developer.
It's now February and nothing of the above has been fixed after > 3 months.