I have the older series Canon TS-E 24mm and wouldn't leave it behind for anything. Best way to make landscape pano shots since the focal point is fixed and you shift the front of the lens. The 45mm and 90mm versions won't cover enough ground for my tastes. TSE lenses aren't light but maybe the newer ones will be.
There is an issue with Uploading Photos (attachjments). I am not sure what the problem is, and I am looking into it. You can still try to Create your Threads and Upload your Photos, but it is hanging up during the Upload.