well I was waiting for someone more knowledgeable to respond, but since you seem to be desperate...
you kinda need to specify an upper price limit, because there's almost no end to how expensive quality gets. I mean, a $2,000 pair of pants will be better constructed than a $1,000 pair. So when you say 'good quality material and finish > cheap price'...we kinda need a top end :)
But for now let's assume you don't want to go too nuts. The good news is that just about any other mall brand will be better quality than Express, I mean, Express is really damn bad. Something as simple/'low end' by SF standards as Gap or Zara is still gonna be better than Express (still not _good_, don't get me wrong, but better). Other fashion-y places/brands like Zara, AX, Boy's Co (god, I'm shuddering as I type this) are probably the best bet if you're super wed to having dress pants that fit around your hips, but I don't know why you'd want that. Why do you want that?
Again sticking to moderately priced mall brands, somewhere like Banana Republic or Club Monaco will sell you some basic dress pants with okay quality at decent prices, so long as you get them on discount. Never ever buy anything at CM/BR-type stores at retail, they are constantly having some kind of sale - if the current sale doesn't cover what you want, wait half an hour and they'll have a new one. If you can stretch to Brooks Brothers prices - again on sale, BB is another place where you shouldn't pay retail unless you're desperate - that'd be another no-brainer safe option.
You could also check out Marshalls/T(J,K) Maxx-type places. Stock in those varies wildly because they mostly buy overstock or returned items from other stores; if you pick one that's located near an upscale retailer you can often find stock from that store on pretty good discounts. But you have to be a bit flexible about exactly what style you want, and know your brands to make sure you don't buy a lemon, and check for damage before paying. This kind of place tends to have more stock in large sizes than small ones, too.
Or there's your friendly bog-standard department store. Not even talking Nordstrom's here. Macy's (or your local equivalent) will have several lines that are better than Express. Again nothing spectacular, but really, 'better than Express' is not a high bar to get over. I think you're possibly not getting much advice because this is such an open-ended question.