Look for cast iron grates vs. stainless, and cast burners vs. the tinny stamped ones.
Go from there.
My old grill is a 14 year old Char Broil with 3 burners, cast iron, and a side burner. Has been fantastic. I added another layer of grating over the burners but under the grill for a layer of ceramic briquettes for much more even heating.
1977 Ford F150 4x4 Shorty 351M/NP435
2007 Ram 2500 Quad Cab 4x4 5.9 Cummins