I use Frontiers in my 9mm,work very well and I cant really see much difference in accuracy between Montanas and them,so I use them exclusively.Only problem is that they seem hard to find at the present.Cant say that I had much luck with them in my 38 super however,lots of keyholing at 10 yards.It seems that these problems start becoming an issue when one goes over about 1300fps.
All in all I really like the Frontier product and they do save a few dollars over the Montanas