"Is it worth paying close to $3000 for an HK-91 rifle when you can get an American made equivalent for ~$1000?"
Depends. What would you use it for, home protection? Or would you just like to possess it?
If the first, then no; get a Bushmaster. If the second, if you can afford it, then go for it.
Some people like to have "safe queens" to pull out, admire and show off. 