q08 or q11 would give me a little more flexibility in my selections.
They give you more flexibility because they are larger. The volume of SG08 is 14.8 L, which is already very large for a mini-ITX case. The volume of the Q11 is 17L. The volume of the Q08 is 21.3L which is almost a micro-ATX case.
It just depends what you're looking for in your SFF system. But it's not like there is anything wrong with Silverstone's design. They are aiming for a smaller form factor, and the SFX PSU is one of the compromises. I like my SFF systems to actually be small, so personally I think the SG08 is already a little too large and I prefer the SG05/SG06. But if you're OK with the Q08, you should also consider Silverstone's SG02F which has a volume of 22.5L and can take either ITX or micro-ATX.