I use a PC, P2 350 with 384 mb ram, which is pretty old for current standards, with Logic Audio Gold 4.8.1 and Wavelab: No issues whatsoever.
In terms of performance, it's a bit resource-intensive, I can only use one when mixing with Logic. Hence I use it for pre-mixes as soon as I have more then 20 audio tracks, EQs, compressors, and two reverbs, so no surprises in that respect. With a more modern setup, you should be able to use it on several tracks without a sweat.
So, considering this limitation, I have a good stability.
As far as Wavelab is concerned, it's more of a coloration and mastering tool, so no problemo...
I just bought it after having abused the demo, especially to give some warmth to vocals. The sound is awesome, I no longer have to pass my recordings through a tape recorder, it's very effective!
I tested Steinberg's tape recorder, but it sounds like a toy compared to the PSP, it's cold an aggressive: It seems they wanted to emulate a distortion...besides, I think it's more resource-intensive.
So, for a similar price, the Vintage Warmer gives you better quality and delicacy for mixing and pre-mastering: It's amazing!
Bottom line, I haven't found anything better in its genre and, even if it's new, I feel I won't be able to do without it.