For what they are, they are VERY well priced, but having seen the amount they flex compared to APs, I find it hard to believe some of the comments that have been posted.
On Churchy's car (Sapphire 4x4), you can actually see the caliper flexing as the pedal is pumped while the car is stationary. Although it doesn't seem to affect braking, it can't be a good thing if the car is to be used on track, and it would always be in the back of my mind.
Unless the design has changed, then you can see why they do this, as it is the way the two parts of the calliper are linked (just by four steel pins). Compare these to the APs or most other two piece callipers, and you can see where the extra rigidity is obtained on the APs.
Obviously as a budget improvement over the standard brakes, they are great, but if it was my money, instead of buying the full front and rear Comp kit, I would buy just the AP front 4-pot arrangement.
At the end of the day, you pay's ya money and ya makes ya choice.