Other than the obvious, the small primer option leaves more meat on the case head which results in a stronger case head and prolongs brass life in the high pressure high bolt thrust rounds like Creedmoor. It's pretty common for the large primer brass to lose strength so quickly that after 2-3 firings they can not longer hold a primer. This is especially evident in the softer brass fro Hornady that is large primer, it's typical for half of the brass two be toast after just two firings. Even 1 firing you'll throw some out when seating primers for the next batch.
Small primer solves this issue but there are some things you have to consider when running the small primer brass. First is ignition in lower temps. This is mostly evident in the Lapua and Alpha brass because they not only use a small primer, but they also have a smaller flash hole. The proper powder selection mitigates this though, the rule of thumb is don't go for slow burning or double based powders in cold climates. The Starline doesn't have this issue however because they use a standard size flash hole which is a nice benefit to the Starline.
Thicker primer cups also must be used to prevent primer piercing as well as your firing pin clearance must be considered or you may pierce primers because of that too. Some people believe you must have a small diameter firing pin to not pierce, but that's not 100% accurate. The clearance or slop between your firing pin and the hole on your bolt face is far more important to preventing pierced primers. You'll want to run a nice thick hard cupped primer as well, so stay away from the federals and all standard small rifle primers, the magnums are what you want as they have the thicker cup and some have harder ones than others. The CCI 450's are pretty much the best in this category as at the BR4's which they are identical too, just cost $20 a brick less. The Remington 7.5's are a close second or better yet the Tula KVB-556's if you can find them but they dried up years ago.
There's some debate over the small primers providing more consistent ignition but personally I have not found that to be true. I've developed loads with ultra low ES's and SD's with both primer sizes in the same chamber. IMO the benefit to small rifle is the stronger brass.
As for the Starline brass itself, it's excellent. I've ran a lot of their 243 brass, I ran some of their 6.5 Creedmoor small primer brass, and currently run their 224 Valkyrie brass and just ordered some 6mm Creedmoor small primer on cyber monday to load for another rifle as well. I love Lapua brass, it's excellent, but the Starline is every bit as good. If Starline makes it, that's what I run. Currently the only thing I'm using Lapua for is 6.5x47 and 6BR but is Starline made it then I would not have bought Lapua.
Probably more info than you're looking for but hopefully it helps.
