King of the Ultrawides, which lens rules?

Let me qualify this, I am not asking in the 16mm and narrower range. I am asking in the 14mm and 15mm range.

I am also making the assumption that I wouldn't need f/2.8 for this lens.

Brian posted a review of the Irix 15mm lens.

Comparing it to the 11-24mm f/4 the zoom looks better at f/4.

http://www.the-digital-picture.com/R...mp=2&APIComp=0

The 14mm vs the 11-24 at f/4 seem to be a mixed bag.

http://www.the-digital-picture.com/R...mp=2&APIComp=0

Samyang it seems the zoom is better.

http://www.the-digital-picture.com/R...mp=2&APIComp=0

I looked at the Zeiss 15mm as well, the zoom still looks better.

Any other options?
Thoughts?

Currently i can say that irix 15mm is my absolute favorite. I had had the lens 1 week after release (amazon.de was slow to deliver) Compared to samyang, beats it really easily. Not only it on my opinnion really supports the 5dsr nicely, it has couple other good things.

I do mostly nightime photoshooting, and so far, haven't had any issues with weather conditions. Samyang and even my canon 24mm II gets really easily wet when there is the nasty humidity conditions, never ever had any with irix. Works also really well on low temperatures, no frosting on the lens yet. The build quality is really good, and what i do love is the infinity click and lock the lens have. So yeah, what i have used the irix 15mm blackstone so far, no need to have anything else (well maybe the new sigma 14mm f/1.8 art to get more variety to nightime shooting)

Everything that I have seen makes me inclined to think that the EF 11-24 is the best UWA lens if you want to go past 16 mm. It comes at a price and the limitation of f/4.

As for the King, I am keeping my eye on the recently announced Sigma 14 mm f/1.8. The Art lineup has been impressive and the MTFs are exceptional for a UWA lens. Actually, the MTFs are better than several of the other Art lenses that have been released. (side note, but everyone is impressed with the 85A....but the recently announced 135A has better MTFs....:))

If you are in the market, do not need f/1.8, and want flexibility and have the money, I would say it is tough to beat the 11-24. However, if you might want f/1.8 ....then I'd wait until the reviews come in on the Sigma.