Well, I hate to be the one to verify this, but your 'best friend' is a dud. It was barely acceptable on film, but it really doesn't cut it on FF digital. This is from trying about 4 samples, and is substantiated by a number of other photographers I know.
I've used most of the shift and t/s lenses available over the years on 35mm and MF. I still have 6 of them. While the 24TSE isn't the worst, it's not that far from the bottom. Just to show that Canon used to be able to make decent lenses a while ago, the old FD 35TS was outstanding; it was one of the very best 35 shift lenses.
The reason I got the 24TSE was of course because it was a 24. Otherwise I would have just kept on using the 28 Nikkor or 28 Super Angulon, both of which are a lot better (but don't tilt).
Canon hasn't had much that was good under 35mm in the EOS line until the new 17 and 24TSE II came out. It has really redeemed their standing as a wide angle lens design company. Their long lenses have generally been good to outstanding, and even their standard lens, the 50/1.8 is fine, if not superb.
I have a lot of other lenses, and I've used even more. Canon's 24/1.4 v1 and v2 are poor, their 16-35's are awful and barely acceptable and the 17-40 is only acceptable. The 20/2.8 is downright useless, and the 28/1.8 isn't much better. I haven't used the 24/2.8 but as for the rest under 35, it doesn't look too rosy. I got rid of the 16-35 a long time ago, and now only use the new 24 and 17 and sometimes the 24/1.4 when light gathering is more important than technical quality. The 35/1.4 gets used a lot more.
Nikon has had some ups and downs, but they've certainly done better in the last while. I'm looking forward to their fast 24 and will try it, but since I'm not really into Nikon anymore won't buy it. Panasonic has made a wonderful 7-14 that I use a lot, and of course Leica has made some fabulous wides in the M line, including the 21 Summilux which is one of my most used lenses now. Yes, it's expensive, but at least you get outstanding quality.
I'm delighted Canon replaced the 24TSE, and now they have to do the same with some of their other wides.
I don't demand superb resolution, contrast, aberration control and lack of distortion in every lens and certainly not every shot, but T/S lenses in particular due to their intended use should be first rate in these departments.
Henning