I am a professional violinist, no way affilitated to either companies. I own Merlins, both VSM at home, and TSM in studio.
So addmittedly biased ;-)
I friend of mine uses ATC active, which is an extremely appealing way of using theses speakers, dont know which model.
For ATC, you will need an absolute first class amplification, rather more, than stated above, imo. Then you will get an extremely full and powerful sound, but my friends room is pretty dead, it being a professional studio..
My merlins go far with small amplification, and I mean very far.. My own room is from early last century, so wood/plaster, the VSM comes along as naturally fast, slim but full, agile but blossoming.
So, be sure to think about room and amplification. I use Merlin with Berning ZH270 to full satisfaction.
In the end, the results are not so far off, funnily enough. hope this helps anyway.