I use this plug-in with the following configuration :
PC w/ Windows Seven, I7-4770k, 16GB, SSD (Samsung 850pro)
Berhinger U-PHORIA UMC 1820
It's better to have a sound interface with at least 6 outputs so as to be able to mix in 5.1. Otherwise, you can also consider using out port emulators...
This plug-in is very stable and light on the CPU. Very easy to get used to, it also has a very complete documentation.
It is quite efficient, but certainly not the best. It was released at $49, but for its current price (twice as much I believe), there may be better from competitors.
An interesting included feature is the possibility to customize the plugin according to your head size. Even if, to complement -or replace- it, the best solution would have been to ba able to choose several hrtf filters...
No calibration depending on the headphone used is offered... a real pity!
The head-tracking feature is rather toyish and inefficient.
For $49, I'd do the same choice again (while still remaining open and attentive to comparable products by competitors), but for its current price... Well, not so sure I would ^^