I sometimes rent the 17 TS-E for interiors. It's an incredible piece of glass. I shoot with 5D3 and when 17 is just that bit too wide I put the 17mm on the 1D Mk4 to get 22mm, get even more flexibility with the very forgiving 1.4TC. Hell, it's time I bought the 17!
The 24 TS-E II is equally awesome, but the 17 is the gold standard with the greatest flexibility for architectural & real estate work.