We've been oven-shopping, too, and find that rating sites are really helpful. There isn't a single one that's perfect, but when four such sites list models X and Y in their top three, you know they're good. It's also helpful to read each one's features in ratings that compare ovens directly rather than reviews.
Once you've narrowed down your choices to just a few, then it's time to read the reviews at Amazon, Home Depot, Lowe's, and Best Buy.
Here are some ratings sites:
Wirecutter--New York Times
Popular Mechanics
Family Handyman
It makes sense to also get quotes for the inevitable extra costs for delivery, installation, and hauling away the old one, as well as how long you might have to wait for your new stove to arrive. One place told us eight to twelve weeks! Uh, no...
Maryn, managing with a stove that has a wonky oven thermostat