Upload & Sell: Off
I have used both, but find that the 24mm focal length fits my vision much more frequently than the 17mm. I find this a very personal matter of artistic taste, as the 17 mm focal length will usually include much more foreground. A minor limitation is that the 17 TSE does not take filters due to its bulbous front element. The image quality is both TSE lenses is quite exceptional, particularly the 24 TSE II, which is crisp to the corners with negligible CA.
Another equipment issue is that to get these very low angle shots with tilt you need a tripod that can hold the camera only a few inches from the ground, and very few tripods will do that. The other issue not mentioned in this thread is that while adjusting shift can be done with a viewfinder, fine adjusting both tilt and focus when close to the ground can be really quite difficult. Live View 5-10X really a necessity; I wouldn't consider tilt use without magnified Live View.
I use the 24 TSE II quite a lot and am very pleased with the results.