Definitely buy it. But I am a bit biased (check my screen name). You're right, even if the gun were a piece of crap, the scope is worth $400.
The 280Rem is an awesome caliber. It is the first rifle I bought and now I'm about the send it off to be rebarreled. With the rebarreling, I could have chosen any caliber I wished. I stuck to the 280. I've taken deer with from very close range out to 300 yards. One shot was all it took almost every time.
From everything that I have read, the benchmark for energy on deer is 1000lbs. The 280 carries that kind of energy out to 500 yards. The benchmark for elk is 1500lbs. The 280 carries that to 300 yards. Shotting at elk, I would want a well constructed bullet like the Nosler partition.
The other great thing about the 280 is if you handload for it, you have an abundance of bullets to choose from.
I'm not gonna shoot here. I'm gonna shoot waaaaaaaay over there!