I think the Sierra bullets are great deer bullets. They can work quite well for heavier game like moose and elk with heavy-for-caliber bullets as well. With the 140 gr .284 caliber I would be reluctant to use them on a moose or elk, but with a perfect broadside shot directly to the lungs it would probably work just fine.
The 140 grain Sierra's are perfect for deer whether in a 7-08, a 280, a 284win, or even a 7mag. They are very accurate , but are cup-and-core designed with a fairly thin jacket, so they will open up quickly. You won't get the penetration depth with them like you would with a bonded core bullet or monometal bullet.
Sierra's website says that their hollow-point bullets are built more stoutly and meant for deeper penetration and heavier game.