I've had speed strips for years and carried them in the past. For me they are a lot slower than speed loaders. I don't care about another bulge in my pant or jacket pocket.
When it comes to J frames I suggest HKS speedloaders. I like the Safariland, but it holds the cartridges very rigidly, making it difficult to use with most grips on J frames, which I carry a lot. The HKS speedloaders have a good bit of wiggle when holding cartridges which make it easier for me to insert the cartridges in a J frame gun. I rarely carry my K frames and I've never carried my only N frame, a Mod 58. I generally opt for one of my semi auto pistols if I'm not carrying a J frame or an old Colt Agent I have.