Fast wide Prime lens?

Zascar

I'm looking to buy a fast prime lens and I'm thinking something around 35mm. I have a Canon 6D, 24-105mm f4 IS, 50mm f1.4, and 70-200mm f4. I use the 24-105 most of the time and I love it but its not fast enough for low light stuff my 50mm 1.4 is just not wide enough. I think I want something around 35mm - I feel this will be a much more usable focal length for low light / indoor stuff.

The one I'd really like is the Sigma f1.4 Art - fantastic lens and gets amazing reviews. The only thing is it's quite expensive, but mainly its big and heavy. So I've been looking at the Canon 35mm F2 IS USM. Not quite as fast as the 1.4 - but still pretty decent and it has IS which will help with low light. Its also pretty small and light.

Does this sound like the right choice or are there others to consider? Are the comparable in terms of image quality or does the sigma wipe the floor?
Comments appreciated

The Ging and I

A 35mm f1.4 is a big lump of glass to carry around. An f2 would be my choice. Im off traveling for 3 months soon and I will only be taking a 35mm f2 lens. I haven experience of Sigma.

Tiriel

I use an EF28mm f/1.8 USM and am pretty happy with it! Sharp, light and has the quality.