The biggest thing I've been missing since I started using FastMail is labels. My workflow in GMail used labels pretty heavily, and I've been able to get pretty close using saved searches and folders, but it's not quite the same.
This has happened to me with labels before, too. I'll do a search for all things that have a label and are in my inbox, and then archive them. I'll then go back to my inbox, and see that it missed something with that label. If I then repeat the search, I get zero results, even though it has the label, is in my inbox, and I can go back and find it. It's extremely frustrating.
I do all of my development on a remote box. All of my work is in a screen session, so I can always reattach to it. Since that box is a lot more stable than my Mac is, it doesn't take much effort to restore my workspace after OS X crashes. I also regularly leave builds and tests running while my laptop's asleep, and, because they're remote, they never cause my laptop to overheat and kick on its fan.
Manta doesn't run on a proprietary OS, but runs on SmartOS, a distribution of illumos [1][2]. In fact, almost everything at Joyent is open source, including all of Manta [3]. As for why not anything else, Manta has been around since 2013 [4], before other similar solutions, and allows you to run arbitrary programs on your data. As an example, some of our customers run ffmpeg on videos that they upload, to produce different variants to then store in Manta.
In addition to Windows and Mac OS X, illumos and I believe all of the BSDs require you to use libc for the same reason. I'm sure that they exist, but I don't know of any kernels other than Linux where the syscall layer is a stable interface. (I'd love to learn about some others though, if anyone knows.)
You might want to try booting without graphics and accessing it via a serial port, to see if that makes a difference. See this e-mail thread for a discussion:
Things that complain about tabs vs spaces and other code layout concerns are style checkers. Linters complain about the actual content of the program, and enforce certain behavior. For example, warning you about unused functions, parameters, and variables, warning on duplicate fields in JavaScript objects, complaining about using parameter lists in C, etc.
Your biggest concern seems to be that a litigious Oracle could come after someone using an illumos-based system:
> It's best to just avoid using any I.P. from a company like that unless the licensing terms protect you in present and future.
But this is exactly what the CDDL does as a copyleft license with a patent grant. There's a good reason why Oracle hasn't gone after anyone for using illumos or OpenZFS: they can't, because these people are protected by the license the software is developed under. The most Oracle was capable of doing was changing the license under which they develop internally.
The rest of your concern seems to be about development effort and the number of contributors. While illumos-developer is not as busy the LKML, there is definitely a lot of work going into continuing development of illumos, and regular improvements.
The search I have the most trouble with is searching for things that match a label and are in my inbox. GMail will consistently miss messages. I don't know what it is about them, but I imagine it's some indexing bug. I can go to my inbox, click through the first several pages of messages, and see that a message is there, and has my label. I can go to my label, and find it there too. But a search for 'label:foo in:inbox' will come up empty.
You can't use lx-branded zones in Solaris anymore, but SmartOS has revived and continued the project, and OmniOS has started porting the bits into their distribution, too.
linc01n's comment was a little unclear. SmartOS isn't doing anything with the LXC protect. What SmartOS has done is revived the branded zones code from Sun for emulating Linux system calls. This means that you can run Docker containers on SmartOS as zones, as well as use dtrace, mdb and ptools on your Linux binaries. You can read up some more here:
In Firefox's developer toolbar (Tools -> Web Developer -> Developer Toolbar), you can type 'screenshot --fullpage' and it will save an image of the entire page for you.
Thank you for your site! When I first started using the shell, I found it useful for discovering new utilities. I still use it whenever I find myself on Windows and needing a cmd equivalent. :)