Just out of curiosity, what is making you move towards Linux?
The huge appeal of OS X to me is, as someone said on here recently, it's basically *BSD with a fancy window manager and 1-to-1 hardware/software integration.
The way OS X is being locked down. In 10.8, signing is optional and even if you tell your system not to allow unsigned, you can bypass it on a case by case basis. In the next OS X, we'll probably move a bit farther in that direction, and at one per year, the OS X of 2016 will probably refuse to run unsigned applications at all, for excellent reasons involving security and malware, etc. I'm sure there will be a way to turn it off, but when it's basically impossible to get more than a few users unless you submit to signing, applications like Bittorrent will either submit or find themselves reduced to developers-only status. If they submit, Apple will be able to remove them at any time (for the vast majority of users, who won't know how or want to "root" their Macs). Even if Apple never chooses to use this maliciously -- and I don't think they would for a long time, if ever -- it's going to be only a matter of time before some group sues them to use it to stop infringement or something.
I don't want to run a system where, by design, the manufacturer can remove my ability to run applications I've installed after the fact. So, even though I'm happier in general with the polish and fit of OS X than current desktop linuxes, that's where I'm headed.
I did mention those benefits in passing: "for excellent reasons involving security and malware". I don't disagree that this can provide those benefits; I just don't feel that they're worth the cost to me, personally. Also, I don't have any notion of how they could provide what I and other technically savvy people want and what the main base of computer users need at the same time.
The only thing you seem to be saying you want is to be free from the fear of unintended negative consequences of code signing.
It's tautological that nobody can both provide something and freedom from the fear of the unintended consequences of that same thing simultaneously.
On the other hand, since the only way to judge the trustworthiness of code is to know its provenance, I don't see how we can avoid some kind of signing becoming ubiquitous.
To me that means that free software must eventually develop a decentralized code signing scheme.
Correct me if I'm wrong, but the package managers of all popular Linux distros (except for Arch Linux, who are moving to bring it in soon) have had code signing for years now. It's not decentralised however the package management system isn't either.
I don't really expect them to take it away completely. So, a simpler version is that I expect the capability to silently disable applications on user machines will be misused (through third-party insistence if nothing else; see the _1984_ debacle at Amazon). A similar system which could only throw up scary warnings when starting an unsigned application wouldn't bother me much, since it wouldn't be such attractive lawsuit bait. But I agree that I'm only speculating that Apple will carry this through to its natural end of being iOS-like. I can't imagine any reason for them not to do it, and I think that for the majority of their users, it will actually improve the experience.
Right now I'm using XMonad, but there are a number of other tiling WMs under X that actually manage windows for you instead of placing that burden on the user.
I don't want to run a system where, by design, the manufacturer can remove my ability to run applications I've installed after the fact. So, even though I'm happier in general with the polish and fit of OS X than current desktop linuxes, that's where I'm headed.