TCS is a valuable addition to most "family saloon" type cars, providing an extra element of intervention to prevent the lead-footed from loosing control in slippery situations. ESP adds in directional control, comparing the steering input to the direction the car is actually going in and correcting using the ABS system.
My TDI 110 has TCS and it very rarely activates, usually only over potholed roads (more of those about recently), gravel and in the wet. I've never felt it to be intrusive, and I think it would be difficult to put a TDI 110 into a situation where the TCS was unwelcome.
With sports cars like the LC and LCR the system seems (from the reports I've seen in the forum) to be too heavy-handed, cutting power abruptly. I've no direct experience so can't be dogmatic, but in general, traction control for sporty cars needs to be sensitive in its control of the application of power to the wheels.
The biggest downside of the use of TCS is that you never get the chance to develop your own skills at throttle control (right foot, by the way, psycho6285) combined with opposite lock. I've taken every car I've owned to a suitable skid pan (piece of waste ground, gravel car park (empty), snow-covered car parks in the winter) to get a feel for what happens when you slip over the edge of adhesion.
You need a lot of space to do this, because you will spin out time and time again, but it is the only way to learn. It is NOT safe to learn this on the public highway, because there are innocent victims travelling the other way who you are most likely to hit when you lose control. And you will lose control, because that's the only way of finding out where the edge is.
Turning off TCS/ESP does not turn off ABS, which is as it should be. ABS is better at controlling brake application than almost all drivers, and entirely appropriate for road use (maybe not for the racetrack, or at least not in its roadgoing form). The most important thing to remember is that ABS is about stopping as quickly as possible *without loosing steering control*. You can stomp on the middle pedal and still steer to avoid the accident developing in front of you. We tend to forget that.
