I've mentioned it previously, but I'll say it again; I wet the bed over mITX builds so I was happy to see another big name bring in a pretty well stocked SFF case but to begin, I'll list my previous favorite cases and their plusses and minuses to show where my priorities were with SFF cases.
Silverstone SG05/6
+ Very compact, well ventilated and nicely positioned 120mm intake to blow over most components, available with 450W PSU at a reasonable price
- Very little room for aftermarket CPU coolers (~60mm), cannot accommodate longer cards >~10 inches (7950 upwards will not fit for eg), uses rarefied SFX PSU, 120mm mount cannot be used for closed loop coolers easily
Silverstone SG07/8
+ Well ventilated with large 180mm fan over motherboard, supports longer cards, comes with reasonable 600W ATX PSU
- Big, expensive, no AIO coolers compatible
Silverstone FT03 Mini
+ Attractive case, well positioned 140mm fan to blow over essentially all components
- SFX PSU, tight CPU cooling space, poor mount for PSU (intake facing CPU fan), larger than SG07/8, expensive
Coolermaster Elite 120/130
+ Cheap, accommodates even the longest cards (7990), 120mm mount in front accomodates closed loop coolers and positioned to blow over most components, no PSU included
- Big, very little room for aftermarket HSF CPU coolers (~60mm), PSU hangs out the back (personal aesthetic taste)
EVGA Hadron
+ Compact, accommodates long cards, takes small tower CPU coolers, 500W Gold PSU enough for almost any build, twin 120mm exhausts, water cooling option
- Expensive, limited ventilation, very tight build
Shuttle - Never considered these since I really prefer to choose my own mobo
Fractal Design Node 304 - A little too large and excessive drive mounts which would be pointless for my use case led me to not consider this case
Bitfenix Prodigy - Large, not even sure this can be considered SFF. Bordering on tower PC territory
Which brings me finally to the Antec ISK-600.
Despite appearances, it's actually larger than the SG07/8. At nearly 4cm wider, 2cm deeper and 5mm taller. What you get in return is the room to mount modest tower coolers up to 170mm tall or an AIO in the back. It takes long cards to 12.5 inches and is reasonably priced at 75 Euro but OCUK have them at £65 preorder. It also takes a slim optical, two 2.5 and three 3.5 drives.
Other things I kind of like - clear front to back flow as most vents are skewed towards the front. This does mean the poor 120mm fan at the rear will have to work its bearings off, to contend with nearly all heat generation from any build including from custom GPU coolers. There are no other fan mounts as far as I can tell.
It shares the most with the Node 304, with its front mount PSU and large rear facing exhaust, which I am slightly split over. I might have preferred to have two 92mm fans out the back and a shorter case.
In short, the ISK-600 seems to tick a couple boxes but still not my ultimate case
+ CPU cooler space, ATX PSU, accommodates long GPUs, clean, smart design which would not be out of place in a living room
- A bit pricey for a basic case, single 120mm fan in a limited ventilation case, not as small as I'd like