I think you made right decision, I my self sold my Sigma 35mm f1.4 for my D800 and got the Canon 35mmf2IS for my 5Dmk2.
I think the small barrel size of the 35mm f2 with IS ,with the super effective IS, is a bit more practical lens in real life than the expensive Sigma or the huge 35mm f1.4 Carls Zeiss or the Nikon version of it, and I even go further to say getting a Canon FF body for just the Canon 35mm f2IS is worth it.
I think the 135mm f2 L and the 35mm f2IS make the 6D and the 5D3 so attractive , Nikon's got nothing like that small but sharp new gen 35mm prime with effective image stabilizer.
Honestly, I have never understood why so many people rave about the Sigma 35mm f1.4 or Zeiss 35mm f1.4 , which I had and used on my 5DMK2 for a couple months and sold.
the Zeiss 35mm f1.4 is ridiculously huge as a prime and it was not that special optically.
I really think the Canon 35mm f2ISUSM is the best (or more precisely most practical) 35mm prime ever made for any SLR system.
I think the Sigma 35mm f1.4 is overrated.