Almost 3 years after I got my 800D, I've finally replaced it with a worth successor - the 750D. I did have a Ximatek Elysium in the middle of that time when I was watercooling, but when I moved back to air, I moved back to the 800D.
First off, the cable management on the 800D wasn't great. The horizontal mid-panel actually pushed behind the motherboard tray meaning that cables got squashed and sometimes got disconnected (particularly SATA cables). It's cooling was extremely poor as it lacked any decent intakes. I actually had to resort to using the rear fan mount as an intake but even then I still had to leave the side panel off most of the time. The PSU could also only be orientated one way (fan down). Overall, though the case looked impressive and the size was more than adequate, it wasn't good at cable management or cooling.
The 750D by contrast is the opposite. Cable management is super easy and there's actually a decent sized 'guide' at the bottom for cables to lay in. There's another guide behind the motherboard tray at the top where you can hang cables and there's no annoying mid-section squashing the cables. The cooling potential of this case looks like it'll impress me - 2 front intakes up to 2x140MM, 3x120MM/2x140MM support at the top, and 1x120/140MM at the rear. Then there's 2x120MM at the bottom but that would require me to remove both drive bays. Since the case has to sit on the carpet, I opted not to install bottom fans. This case also allows me to mount the PSU with the fan facing upwards so I've taken that route this time. More to the point, it's got front USB3 ports. Sure, you could buy a backplate for the 800D for the same, but I never opted for that.
The 750D is slightly smaller than the 800D, but I'd say it's just the right size in all honesty. At the same time as I got the case, I also ordered in 3 AF140 fans - 2 to replace the front stock fans with and 1 to replace the rear stock fan with. I remember that the stock fans on the H100i rattled a lot so I didn't want to risk it happening again with the 140's they fitted. I had planned to order in a 750GB Samsung 840 EVO as well, but finance got declined so I had to buy what I could afford this month (which was case and fans).
Thankfully, it's light enough today to get some semi-decent photos;
This shot shows all the hardware actually in the case prior to the PSU being fitted. You can see that almost all of the cables have been hidden completely from view.
This provides a better view of how it actually looks from the side but again, this was before the PSU was fitted.
PSU fitted - the typical bottom corner shot. You can
A better view from the side after the PSU was fitted. You can see there's a lot of cables at the bottom, non-modular PSU so I've got to 'deal with it'. The rest though, as you can see, is still rather tidy.
An even better view from the side, all powered up.
Honestly, this case fixes all the problems I had with the 800D, and then goes the extra mile. For example, the SSD mounting is impressive - though they're "only drives", they're still expensive hardware and it's good to know that when I finally replace the old SSD's, I'll be able to show them off. I've got 2 HDD's in this rig, both 2TB, so keeping them cool is now finally an option (800D did have mounts for them, but the air wouldn't really have gone anywhere). The case also seems quieter, presumably because of the number of rubber mountings around fans and such. I mean, even the HDD mounts are tool-less but flexible and silenced.
The only thing I will miss from the 800D is the push-button mechanism for the side panels. That was almost pushing me towards the 900D instead but in the end, thumbscrews aren't so bad.
Final conclusion: The 750D is how cases should be - easy to work with, impressive airflow, fantastic in expansion potential but conservative on features. It looks sleek and really does let you showcase your hardware.