They are certainly worth the little money that say a Competition Electronics ProChrono costs. I will say that I see using one as essential when developing loads for double rifles considering the nature of "regulation" where the balance of bullet weight and velocity determines the time that the path of the projectile is being influenced by recoil. As you may know regulating DRs is all about the Devil being in the details. I use mine for all of my load development, even scoped guns, just because I like knowing what my loads are doing but I'm sure most could do without one if they're shooting scoped single barreled guns and following recipes from a reloading manual; I went without one for a long time before I bought my first double.
I personally have been using a ProChrono for years and it has served me well.
