I tried and tested BricsCAD. First the 'BIM' extension to see if I could replace Revit entirely, then the plain 'vanilla' version. This was the second time I tried it out. To be honest I felt like they went down the wrong route; they seem to be following in Autodesk's footsteps in that they are adding a bunch of new flashy features which will barely see any usage, but not fixing/refining the basic features. An example is there parametric block system. They were bought out by a larger company named Hexagon.
BricsCAD performs incredibly fast. Also, from what I hear, the DWG file compatibility and stability of the program itself is top notch; maybe even better than AutoCAD. I am still thinking about getting a BricsCAD Classic license. But I would still need a AutoCAD LT subscription to use in conjunction with it. The cost of BricsCAD seems to have gone up as well (and the cost to upgrade).
I'm going to try ProgeCAD (I remember good things from a previous test/trial, but I think it was a bit unstable) and maybe one other alternative before making a firm decision. I wonder if, that since ProgeCAD is still based on IntelliCAD, LISP programs will perform well with it.