The main reason to pick an AI type receiver is a rock solid reliable trigger assembly and user end barrel changing. Other than that, the AI is pretty much just a flat bottom action that takes mags. AI rifles are heavy which can be a pretty big downside.

I shot a T2K for many years and it is an amazing rifle, but can be a bit too delicate to drag around a dusty and ugly range. For High Power you wont find a better bolt-gun.

If I was going to build a new rifle it would use either a Bighorn Action or a Badger AI clone action.

If I was going to buy an off the shelf rifle, it would be an AIAW/X or something from GAP or Surgeon.

Gas guns like AR-10/SR-25/OBR are good, but harder to shoot well. My OBR is getting a 260 barrel right now so time will tell. I will be a newbie at long range with a semi.

Barrels are pretty much just two flavors. Button rifled and cut rifled. I have used both and have had good luck with both. Right now I am using Lilja and Brux.

For stocks I like Manners for a fiberglass and AI for a chassis.

For scopes Nightforce and S&B are the way to go.

Harris bi-pods or the norm, but the Atlas is very good and better in many ways, price not being one of them.