Now let me start of by saying that this plug-in truly deserves its name. T-RackS is a beast. It looks just like the hardware unit you never had the money to buy and actually sounds like it, too. So be prepared to let the T-RackS add color to your music, for it's far from being sound-neutral. But this particular coloration of the sound is actually very appealing and nice. And even if you're not a fan of subtle valve overdrive, this thing can give you some decent digital distortion.
Though some people nowadays seem to avoid remodelling old vintage gear, because they think it's not very useful to have rotating knobs when you only have a mouse to control these knobs, I think in this case the designer did a wonderful job. The only 'negative' aspect of the GUI is the repeated application of the T-RackS logo, but this of course is due to the fact that one can use each module of this suite on its own. This again is a very nice feature to save CPU load and screen space. A unique and quite useful part of T-RackS is the ability to patch the different modules in a different order (EQ-Comp-Limiter or Comp-EQ-Limiter-Clipper etc.). So this way you're free to use the whole suite and are still able to change a plug-ins (routing) position.
To start off T-RackS offers more than 100 presets. Some presets are changing parameters of every module in the effect chain (suite presets) others are for a specific effect only. The EQ-presets for example are split into FX (telephone, boom box etc.), generic and mastering and all really do what they say. Only the preset browser might need a rework for it's kinda hard to browse thru the different presets, when the scroll button makes movements way to fast. Maybe a scroll bar would be a nice little feature to add.
During my testing of T-RackS I ran into problems with the mono versions of the EQ, Tube-Comp, Multiband-Limiter and Soft-Clipper. Whenever I wanted to apply them to a track (this happened with mono and stereo tracks) the CPU usage jumped to 100%, while the stereo versions were using only 5-10%. So I couldn't use the mono versions at all. But the stereo versions worked quite well on mono tracks, too. Still it would be nice if this bug gets sorted out (and it is with the new version)
So if you're interested in an all-in-one mastering solution, this could be your toy. Maybe a mastering reverb would be cool but as you might know: SIR which is a free impulse reverb which does a pretty decent job there. Compared to other mastering tools like PSP's VintageWarmer, T-RackS adds more of its own color and character to the sound, and has more knobs to tweak (which btw doesn't necessarily make it harder to use). So if you like its sound and if you have enough money, for it’s not the cheapest bunny in the mansion - this could definitely be a good alternative to spending the same amount on two or three days with a good but busy mastering engineer in someone else's studio. And like I said, all in all this is a superb tool