I purchased the Neal Waltz die and it is TOP NOTCH!
Like GWarden, I found improved accuracy with some brands.
There are two advantages to the Waltz die:
1. It provides a means to flat point .22 rimfire bullets.
2. That flat-pointing operation also swages the bullet to a slightly larger diameter and does that in a very controlled manner. That increased diameter can result in improved accuracy.
The real advantage is the die allows you to squeeze better performance out of low cost bulk cartridges.
Years ago, I sorted cheap .22 cartridges with a rim thickness gauge. Again, the advantage is the process allows you to increase the accuracy of cheap ammunition. Of the two techniques, I think there is FAR more value in the Neal Waltz die than the rim thickness gauge (which I believe was made by Sinclair. If memory serves)
I can highly recommend the Neal Waltz die. In today's environment of re-occurring shortages, there is benefit to having that die. You can squeeze more accuracy out of bulk rounds (maybe not to the highest level possible with high quality target ammo but better than cheap ammo)
The flat point also makes a good small game bullet.
There's a hollowpoint pin included but, IMO, the flat point is a better option.