Hi,
on my nearly 4-year-old laptop (specs. in 1st post), if 300 units - each consisting of a skeletal mesh and a flipbook lod - are on screen, and animating/pathfinding/moving/colliding, FPS stays continuously over 30. Until this, the bottleneck is my GPU hardware, around 400 units the bottleneck becomes the game thread, min. FPS is about 25, which is great because it means I can optimize it further by e.g. better collision avoidance (movement prediction), multi-threading, or path sharing. When less units are visible (top down camera), or more units are idle, FPS is increasing nicely to slightly over 40. In near future I will make a new testbed level with a town, where a different more advanced formation positioning system is used, what costs a bit more performance, but works more smoothly in crowded areas. So there are a lot of things to implement/test on my to do list. 
I planned to post screenshots always with unit stats, but sometimes I forget it… :rolleyes:
By the way, what about your marketplace RTS product, how well it performs with a few hundred units? I guess it uses the built in navmesh pathfinder.