I’ll preface by saying that this is not an official statement on behalf of Canonical as far as I know, simply a post on /r/ubuntu. The user is the Ubuntu Community Manager and his post about SecureBoot pretty much sums up my own opinions.
His post in its entirety:
I think we would all agree that this is terrible that Microsoft are putting other Operating Systems in a position where either (1) they have to sign keys to boot, or (2) we have to ask users to switch off something in their BIOS that has “secure” in the title.
While mal-ware is indeed a threat, and quite nasty, I would have preferred to have seen a means in which a solution can be found that is not controlled by a large corporation who themselves has an Operating System product.
From an Ubuntu perspective, we are going to do everything that we can to ensure our OS boots on the widest range of hardware possible, and the story that Matthew Garrett tells is similar to our experiences in the Ubuntu world. Matthew’s story, and the challenges he has explored are not specific to Fedora, but to all Linux distributions.
I think the problem Microsoft is trying to solve is admirable…mal-ware at that lower level is dangerous, but I think the solution is putting companies like Canonical and Red Hat in a tough spot. 
This hits the nail on the head, really. Microsoft is trying to solve a problem and that’s great but in doing so they are putting distros and Linux users in a difficult place. As he says, it’s now a matter of supporting SecureBoot and paying VeriSign or asking users to disable a security feature.