IMHO, Solus is the most promising new distro around, as it essentially combines the user-friendliness of Ubuntu with the rolling up-to-date nature of Arch, along with the stability of openSUSE Tumbleweed. You couldn't ask for a better mix!
Also, the developers behind it (/u/Ufee1dead & /u/joshstrobl) are pretty awesome, and very open to user input.
And for gamers Solus is absolutely superb, as it has an excellent Driver installer tool like Ubuntu, the latest stable AMD drivers, as well as the stupendous Steam integration package, which makes Steam run just like it does on Windows. (With other distros, right clicking in text fields on Steam would never work properly).
Oh, and the Budgie DE is pretty flippin' sweet.
As for negatives, the only things I can think of right now are:
So overall, I'd say Solus is right up there with the likes of Ubuntu MATE in terms of quality and usability. I anticipate it will become one of the major distros within a few years, heavily competing with Ubuntu and Fedora's market share. ^_^
Cross-platform repositories sound dodgy as hell. Are you in a position to compile it?
If this is what you're after, it's on github:
https://github.com/mate-desktop/caja-extensions
Compiling's often not that difficult. You could start with a VM, download this, then enter the downloaded directory and:
> make
> sudo make install
If it tells you 'oh no! You don't have thing X!', then install thing X and try again.
If the VM's working a day later, it's probably fine.
This is probably a bit to specialized for this subreddit. You could try opening an issue with caja-dropbox, or even compare the closed issues to see if you get a hint.
Errors aside, I don't think the link that you gave has the functionality that I was looking for. It has only image-converter, open-terminal, etc but not anything related to "columns".
Having a look through what has been done with the underlying issues with Python-caja this should now be fixed.
https://github.com/mate-desktop/python-caja/issues/22
https://github.com/mate-desktop/caja/commit/8a826a675862d56b6d01c8467282bde9171f8cf8
I'm running 16.04 since the first Beta, I have not run into this issue. I see no reason why this issue should not be resolved once you are running 16.04 as the fixes are now in place.
You can wait the few days until 16.04 is released or force the upgrade now to test it out.