I've heard nothing but good things about the boresighter sold in the Dillon catalog. I especially like that it doesn't require any bushing or adapters to fit more than one caliber. For $100, that's pretty good.
The laser gadgets that look like a bullet and fit in the chamber are pretty nice, but they get expensive when you have to buy multiple bushings to fit your various rifles. I don't have any experience with them, but I could see the purchase if I never, ever wanted to sight a different caliber. Doubt that would happen and would recommend the Dillon muzzle-mounted version. Heck, you know a buddy or two is going to want to check their weapon once they hear you have it......