Since the licensing for MT changed I bought it. OMG - it is so freaking awesome. I can't tell you how much I loathe using the other "popular" directory now. It is so nice to have all of the features integrated with the component without having to hack everything together. Plus - it is just so slick. The modules are very customizable and are integrated with filtering and rules to interact with the component. Every add-on module an and plugin is INCLUDED - you don't get screwed having to keep shelling out money (or getting stuck with a commercial license) every time you want to extend its functionality. ITS ALL INCLUDED and is designed, by the developer, to work together. I'm very happy.
There are two negatives. First, is that the template that comes with it default doesn't showcase the listings and capabilities of the extension well. There is a $50 template pack that solve this. So, it's not really fair to call this a negative. I couldn't be happier with my template investment and would highly recommend it.
The other is that there is no radius or distance search. There is some talk on the forums about adding this, but seriously, the distance search is its only true shortcoming.
One other thing is that there is a third-party payments system called PaymentsPlus associated with MT, but for me it was hard to find (it is in JED and I only recently stumbled upon it). PaymentsPlus recently went GPL as well and it extends a package purchasing system for listings that further distance MT from its competitors.
After spending many years on an alternative directory system, I am switching all of my sites to this.
To me, this is everything that on open source project should be. A GREAT product, at a fair price, with a GREAT third-party add-on.