Keith, tilt-shift expert extraordinaire has posted his review of the TS-E 135mm F4L Macro.
Detailing not only sample images, but details on why you'd use such a lens in the real world, Keith's review is a must read if you are thinking of purchasing the TS-E 135mm.
His conclusions;
What a lens – in many ways one of the best quality lenses I’ve seriously tested.
The 10º of tilt, 12mm of shift and wide open sharpness make it a joy to use for product photography, giving a level of creative control previously more in the realm of large format view cameras. Make no mistake, this is a lens that you will have to work with to get the best from.