I have owned both the compact model and the gun type Stop-N-Go repair kits for 10+ years. I carry the compact one on the bikes and the gun type in my truck. I'm in and out of a lot of nail/screw ridden construction sites with the truck and would estimate that I've plugged 20+ tires over the years. I've done maybe 5 or so on the bikes. Each and every repair has been successful and I have never experienced any loss of air over time. A couple of the truck tires were run for 30k plus after the repair. I do agree that the gun type is a bit bulky and both types are a little fussy to use, but I have had good results with them. I will say that all the punctures have been nice, round holes. If we're talking about any type of slash or oblong puncture I would say that the sticky rubber plugs would be the way to go.
Just my two cents worth.