Well for one thing, the Maldol is a true mobile antenna that mounts using an NMO mount. What you have there is a window clip-on mount that has a female BNC connector on the outside. The Maldol will not connect directly to that clip-on mount.
The item you have pictured is made to work with handheld antennas that you want to place outside the vehicle to improve reception. In that case, I would recommend using the Diamond RH77CA, which is a ham 144/440 dual-bander. It will work great for VHF/UHF, but will not perform as well at the 800 range. If you're only listening to local 800, it might do well enough for you there. You could use the Radio Shack 800 duck, which is most excellent at 800, and works decently at UHF and little less so at VHF. It just kind of depends on what your primary target is. I would recommend when you are not using the clip-mount that you move it back into the vehicle though. It is not what I would call weather proof, nor would I want to leave the antennas I mentioned out in the elements full-time.
Personally, I would go the mobile antenna route with a mag-mount. Just route the cable into the vehicle and connect directly to your scanner (using the required connector adaptor). I think your reception would be better with that setup than using a handheld whip with the mount you have there. Plus, the mobile mount would be more weather resistant in case you want to leave it outdoors all the time or if you are driving in bad weather while listening. Again that is just a personal opinion.