I would definitely go with the 9500ci over the K40. I will say the laser jamming capabilities are greatly lacking with both systems. If the 9500ci is ever offered with just the radar detector and without the laser jammer (it comes with the Escort Shifter ZR4)... I will be buying it.
There are a few effective laser jammers out there but the best the laser interceptor. It runs about 700 dollars for a two head unit. If you want protection in the back, you'll need an additional two heads which almost doubles the cost.
Here is a video on the K40 failing miserably to jam laser:
YouTube - K40 Laser Defuser doesn't work!
Here is some some more information on other laser jamming systems:
Radar Detector Tests and Reviews by Guys of LIDAR