As others stated, you should decide based on focal length only. Personally, I picked the TS-E 24L II as my preferred focal length, after spending some time shooting my intended TS-E subjects with at both 17mm and 24mm (testing was actually done with the 7D + 10-22mm; I bought the 16-35L II and sold the 10-22mm about a month after getting the TS-E 24L II).I was talking mostly about functionality. You can crop a little but cannot always go backwards.I bought the 17mm TSE II (incredible) Lens first...based on the fact that (much to my surprise), I could use my Canon 1.4X III to increase the focal length of the 17mm to 24mm and get as-good (OR BETTER !), IQ as the 24mm TSE.Better? If you're referring to the original TS-E 24L, maybe - but the TS-E 24L II is sharper than the bare TS-E 17mm, and decidedly sharper than the 17 + 1.4x (very obvious in the TDP crop comparison).