Got my CM690 today, quick overview..
+ Looks nice, pretty spacious
+ Fans on top keep temps down, cpu is under 30 degrees idle

Really temps are low enough not to have to both with watercooling.
+ Fairly quiet, I'm running.. 2 * 120mm fans up to, 1 * 120 mm fan on the back, 2 * 120mm fans up front. Nice.
+ Potential to mod and saw and chop.
+ Plenty more fans holes all round for extra fans, even 80mm fan onto the back of the cpu.
+ Decent hard disk mounting, good enough tool free mounts.
+/- Top E sata and sound and firewire and usb wires are awkward, but importantly you can unscrew them and chuck 'em away.
- Pain in the ass routing for psu cables, have to hide them all around the right hand side of the case. My psu isn't modular and has ~ 11 cables so is hard work to route cables.
- Stock fans are awful, not much airflow from them although quiet.
- Might need to mod and saw and chop to sort out the cable routing round the back.
- Power LED doesn't work because it's only 2 pin, not the 3 pin used on most motherboards, with a gap between the + and -. Annoying.
- Power and resest buttons are pretty poor, what with being on the side.
More than I was hoping to write. In all a decent case for the money, 50 quid delivered is pretty fair. Going to mod my power supply I reckon.. and chop off some of the extra molex dongles. Enjoy.