Buying a controller: Terminal Mix 4 vs 4Trak

Can’t really say much about the 4Trak as I’ve never used one but the Terminal Mix is a very sturdy 4 channel controller, which works great with Traktor or VDJ (a skin is available). The jogwheels are excellent, particularly if you’re learning to scratch. It’s bus powered meaning no additional PSU (if that’s a plus?), you can plug in 1 extra sound source (line/phono), but it can’t be used as a standalone mixer like the Numark. It also opens you up to the world of Serato which will give you tighter jogwheel control.

Actually I found that both (TM4 and 4Trak) are not extremely well suited to scratch in Traktor. But then I have yet to find a controller I am comfy with scratching on Traktor apart from the S4.
However the TM4 is BY FAR in my opinion the best controller to scratch on for Serato and VDJ, where as Serato is THE BEST software to scratch on to begin with. I have yet to find a software that, without altering any settings, is as responsive and latency free when scratching as Serato and even though the TM4 does not have LEDs on the jogs, they are by far the best non-motorized jogs I have ever touched.
For scratching hands down TM4+Serato BY FAR the best, with VDJ being close second when you follow the tuning tips for VDJ you can get the latency nearly as close to perfect as with Serato.

While the 4Trak is an excellent controller for Traktor and VDJ, it has decent jogs, but not as good as the TM4 and it is neither controllers failure that scratching is not as latency free, as NI just does not support HID on any controllers but their own for jog performance.

Well I cannot look inside the software and see if the 4Trak does use HID, however if it does it is way worse than the implementation in Serato.
Do not get me wrong, you can scratch on the 4Trak and prolly pull off some stunts even, but when I compare it to the TM4 with Serato they are lightyears apart.
Of course all of this if scratching is your primary goal and you want to pull of things like DJ Angelo when juggling and scratching.
If your are only going to put in a baby scratch or a flash here and then and the rest you do is effects and mixing, then the 4Trak is awesome.