It's a good bit of kit. It's quite heavy at nearly two pounds and a bit bulky so, to be honest, I only take it when going on longer tours or when there is a bunch of bikes going out.
I used it to plug a brand new tyre on my Blackbird and then proceeded to do about 3,000 miles around France, no problem, at well over 30 mph! On my return I had the tyre professionally plugged, from the inside out, at a dealers but on inspection not sure that I really needed to.
Tips (sorry if it's grandma and eggs)
(a) Don't pull the offending nail or whatever straight out without marking the hole's position first. It will be a b*gger to find it afterwards.
(b) Have a go at reflating the tyre before pulling the object out. Tubeless tyres are pretty good at sealing around screws and may hold just enough air to get you to somewhere better to work on a repair.
(c) As Fanum said, take time preparing the hole. Ream it out a bit, don’t worry, you are not making it an awful lot bigger. The air pressure in the reflated tyre pushes the mushroom head against the tyre wall, completing the seal.
(d) The few gas bottles you get are sometimes not enough to fill a large tyre. From memory, they are the same size as drink sparklers that you can get in bulk from Boots at a few bob less.
(e) To avoid carrying the bottles I bought a very tidy small bicycle hand pump (got it from one of the better bike shops catering for expensive racing bikes). It pumps air in on the ‘push’ and ‘pull’ strokes, so reducing the effort. Works a treat and is good for dealing with some of the slow leaks you get with tubeless tyres.
(f) Have a practice using the gun first. Dealers will give you an old tyre for nought. Otherwise it’s Sod’s Law that you will need to use it for the first time on the side of the D147 from Lower Snotcombe to Upper Jumper on a very hot (or p#ssing down) afternoon.
(g) Be sensible about where the hole in your tyre is. If it is way off the central ‘safety zone’, either wait for recovery or plug it and ride very gingerly. The side walls are a no-go area IMHO.
(h) In an emergency, do what the couriers do. Carry a reasonably stubby self-tapping screw in your jacket. If you get a puncture screw it into the whole. It will act as a pretty good ‘Get you going’ plug, providing you can pump the tyre up.