Macbook Pro i7 3.2GHz. It runs smoothly. The plugin is still hungry, which is not surprising coming from a plugin saturation. The plugin is stable.
I was part of the BETA team that tested loan three months before its release. Interestingly, I have a preamp tube SPL (Goldmike) which I use as "Tuber" mastering. I use it to add saturation to cold mixes. I was surprised to find a lot of similarity between it and the plugin tube mode. I spoke with Tony Frenzel (the man behind Klanghelm) and found my comment funny, because in fact using a preamp SPL to its comparison with analog.
In short, it is an excellent product and value for money is simply stunning.