You mention pellets grills, I have a traeger grill. I love it! You can smoke, grill and even bake on it! I remember reading that you could sear on it to, but I have never tried so I can not confirm that. I know you can not use pellet for stoves in it as it would affect the flavor and I believe thay also have toxic chemicals in them, how ever you could use the smoker pellets in your stove, but I am sure the pellets for a smoker are a little more then the pellets for a stove!
As for Webers, never owned a gas grill, but if the charcoal grill are any example you should be good! I have had a Weber charcoal grill for over 15 years and it's still going strong!