I tested some VST with a midi keyboard.
1) Thorn
2) Sylenth
3) Kontakt
4) Predator
5) ANA
6) Omnisphere
7) Dune
8) The Legend
9) Diva
10) Avenger
11) Serum
Reason supports different VST, but using too many VST in a track could be a problem (computer can't handle the processing).
(maybe my PC is too slow)
Just for the information :
I have problems with my 5year old computer , Intel i7-2600k CPU, 3,40GHz-3,70GHz, 16GB RAM , without ssd drive (windows 7)
But on my notebook its better (1y old) : i7-7500U CPU, 270GHz - 2.90Ghz, 16GB RAM, 1000 GB HDD + 256 GB SSD (Windows 10 )