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.
5D3, 5D2, Sony α6000, G16 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: SY12 f/2, Ʃ19 & 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses