Viking: This range is eerily similar to their first range produced back in 1990. Probably because they haven't changed it and have offered upgraded models. I still like this range. Burners aren't sealed, but you can't lift the whole pan to clean unlike their sealed competitors. The BTU's are basic at 15,000 with a 700 BTU simmer. As a reference, a 10 year old range has one 12,000 with an average simmer of 1,000 or so. Unit is available as a 6 burner, 4 burner grill or 4 burner griddle.
Wolf: Wolf became interesting when SubZero purchased the company. Unlike the previous regime, they actually invested money in the company. This unit has semi sealed burners with a 16,000 BTU and simmers well at 500 BTU. Semi sealed means burner is mostly sealed (more than the Viking), and the trays can lift off for cleaning. Unit is available as a 6 burner, 4 burner grill or 4 burner griddle.
KitchenAid: I actually like this unit. Unlike Wolf and Viking, it is not available with grill and griddle, BUT is self-cleaning and has clock and timer. KitchenAid also has 2 20,000 BTU burners.