I had many of the cheap $99 grills (char-broil and others) for years. They never were any good, but I just didn't know any better. They did not retain any heat, never got really hot, and rusted through in just a few years.
Then my wife won a Weber Genesis in a chinese auction. I couldn't understand why the retail price was $700. Who would pay that much for a grill, and why? But I shlepped it home anyway. Boy was it heavy. Know why? Because it is all heavy cast iron and steel. It can get very hot and it keeps the heat inside. Once I used it and experienced (and tasted) the difference, I understood. Not only does it grill better, but I am expecting it to last for many many more years.
I can vouch that there is just no comparison between a heavy-weight brand-name (it is possible that Weber is not the only one,) and a light-weight cheap grill.
Now I am so spoiled, I am actually shopping around for a rotisserie attachment for my Weber!