Corey, I switched from a 16 yr old Genesis 3 burner to a 320Q two months ago.
Reasons:
1)I wanted more room on the patio.
2)The 320Q gets hotter than my old Genesis, plenty good enough for a nice sear.
3)the Q series are way easier to keep clean.
I cook sometimes 5 out of 7 days on a grill and really put the Q through it's paces - direct, indirect, combination and griddling. I regularly use the Grill Grates aluminum grates for high heat burgers, steaks and fish. Perfect sear marks and VERY juicy results. I use the Vic Cherikoff teflon Hot Sheet for any messy stuff. I cook indirect by placing a shallow foil pan under an auxillary cooking grate laid on top of the Q's grates - Captain Cook's reccomended method.
BTW, I gave that Genesis to my son And he is still using it. It works just fine.
All that being said the bigger Webers will do all those things as well or better. I cook for just 2 to 4 people. If I really needed more cooking surface I would not hesitate to go with the big 320 Weber instead of the Q. But I would stiil prefer to clean a Q any day over the big Webers. For someone that cooks as often as me it becomes kind of a big deal.