I've got the old 100-400 and love it but my IS recently went buggy. It'd gone out in January but came back to life and then died again about a month ago.
Does anyone know about or have experience with getting a lens repaired near end of life? I'd send it in now if I had the cash available, but just finishing grad school and so it hasn't been a priority. I figure they'll have some spare parts around still once the new lens is released. But for the sake of hassle and cost, should I save up and send my copy in as soon as I can?
I would suggest you to contact your Canon service center and get a quote.
5Dmk3, 5Dmk2, Sony NEX-6 | SY14mm f/2.8, Ʃ20mm f/1.8, 35mm f/2, Ʃ35mm f/1.4A, 50mm f/1.8 I, Ʃ50mm f/1.4 EX, 100mm f/2.8L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: 16-50 OSS, Ʃ30mm f/2.8 EX DN, 55-210 OSS | 2x FT-QL, AE-1 Program, some FD(n) & FL primes