I currently am running QTP cutouts. Have been on the truck for 2+ years. The only problem I ran into was my driver side motor wasn't closing perfectly. I called up QTP and they sent me a brand new one... No charge. Now that's customer service. When it comes to you buying your cutouts, you get what you pay for. I have heard of some bad story's of people losing cutouts on the highway because of bad mounts and poor build quality. The QTP cutouts are a great design, and are built great and install is straightforward. I have heard some guys complain about exhaust leak with the QTPs... but the motor can be easily re aligned.
If you decide to go with QTP, here are a few tips.
-like said above, keep your window/door open when adjusting valve until you hear it fully close. I usually hit the button one time after it's closed to make sure it's shut as much as possible without straining the motor.
-if you need to open/close valve on road, try to do it below 1000 rpms, anything more is stress on the motors.
-about once every month or two, use some break cleaner to clean off the cutout, and spray it down with some penetrating oil. The cutout can get a little messy, I have some soot buildup on my front drive shaft... and I don't have a cummins lol
Hope this helps out, good luck!