Level 10 GT
I have the Level 10 GT case.
Level 10 GT is very sturdy and has a very convenient handle at the top. This handle easily takes the weight of the components and is rather comfortable to carry it by, truth be told.
The 3x 200mm fans are very quiet and probably best left at low forever. No point going high. High noise, little temperature difference.
Very easy to disassemble case for cleaning and and all fans have very easily removable dust filters. The door's fan does not connect by cable to the case, so you can take it off entirely without thinking about it. Sidepanel (other side) is a pain to fit on after assembly, as the four corners are tricky to align well.
No tool-less operation in mounting HDDs, but they're all hot-swap bays and easy to manage as long as you don't lose your screws. (Like I did!
The Phantom is great, but feels plastic, and is prone to fingerprints or grease (particularly black version).
It has a great fan controller by default though. I'd argue that you can keep it at all low though. The noise is a gentle hum and I don't think the temperature differences between low and high is notable.
Mount powersupply and prepare the 8pin before mounting the motherboard though -- the slot you feed it through at the top is too small to let the cable through while a motherboard is there in certain revisions.
Beyond that it's easy. Punchouts on motherboard tray allow you to tie cables quite freely, and the sidepanel is attached like a door, so you can easily squash cables against the tray. I do not recall however if the cut-out matched the processor-position.
This one has really convenient stand-off chart right on its motherboard tray. However the cut-out does not match Sandy Bridge users. (Neither does the CM 690 II Advanced.) The fan cables were awkwardly short though in my opinion, and particularly the sidepanel fan could have used a better solution.
Otherwise it's... insignificant, to be fair. Easy to build in. Sidepanels go on like doors, so you can squash those cables, and building in it is generally easy if you're aware that cutout may not match your processor's backplate position.
CM 690 II
This is actually very similar to the HAF X in building, but has two added tradeoffs. Firstly, the default setup is a negative air-pressure, so I'd recommend another fan. Two more if you're using a watercooler, and one for every exhaust you add on top.
And the sidepanels need to "slide in" on their sockets, while space behind the motherboard is a bit tight. This makes it incredibly annoying to fit the sidepanel on the backside with the cables in place.
There we go
That's it for my computer building experiences, sorry.