Even though you state Weber is way out of line price wise, my vote goes toward Weber anyway. You simply cannot buy a better grill, in my opinion. Toss some cash on top of what sister is offering if you can, it's worth every penny!
It's difficult most of the time to see the quality in a Weber, I was one of those who thought I would never spend the money on one. That was until I was gifted one...now I own 4 of them!
My first one was over 10 years ago and I still use it...a fire engine red Genesis gas grill. Followed by their Weber Smokey Mountain Smoker, a 22.5" Charcoal Grill, and finally, last year I found a fantastic deal on a new stainless Genesis that I just couldn't turn down. I still use Big Red most of the time, firing up the new one only if there is a ton of food to cook.
There are subtle differences you start to notice over the cheaper options. First thing I noticed was the heat retention of the thicker gauge steel and porcelain coating...as opposed to powder coating. The cooking surface no longer had "hot spots" and the lid temps returned to proper cooking temps much quicker after opening to inspect and flip.
Parts are thick, sturdy, well though out and easy to clean. It is quite literally the only grill I've owned that didn't feel like it was falling apart after the first two years. The support is unmatched. I Recently called them up to get an ignitor for Big Red, even though the grill is well over 10 years old, they still refused to let me pay for it.
All in all, you simply cannot go wrong with a Weber.
Peace,
PHRoG