I have Staintuns and I like them a lot. Sceptres are definitely louder. I've ridden with a guy who has them. I think the Sceptres can be repacked. I think I remember him saying that he needed to repack them.
The Staintunes are stainless steel so they will last a long time and won't rust. The only problem with stainless is that it turns yellow if your bike is tuned too lean (hot).
Staintunes are a straight through, absorber type pipe, which means you can look through them like a telescope. They have packing along the inner wall so that when the exhaust pulse travels through the pipe, it expands into the packing, thus losing some of it's energy and sound. They have one reducing baffle on the very end which you can take out. I have heard from others on this site that it doesn't increase the sound much to take it out. I have left mine in.
That is different than the OEMs or the TORs, which are a baffle type pipe. With those the exhaust travels through a series of baffles and expansion chambers. The exhaust pulse is choked down and then expanded, choked down and expanded, until most of the energy and sound is squeezed out, and it is nice and meek and mild when it comes out the end.
I have drawn looks from cops as I rode by. I'm not sure if they noticed the sound or if they were just enraptured by an extremely unique and beautiful Triumph going by.

Anyhoo, I like the sound, and the little white haired lady who lives a few doors down told me one day that my motorcycle wasn't annoying. So there you have it.
cody