I'll be replacing a 16 plus yr old Whirpool Dishwasher soon.
1. Anyone know if there are any brands that stand out above the rest?
2. Is it a good idea to buy extended warranty for a dishwasher?

Thanks... (I've got to go wash dishes now)

Matag is a good respected brand.
About the warranty, it will have a good warranty on the machine, and any machine should last well past the warranty, so it is very possible that you would have to purchase an extended warranty after the first extended warranty expires to ever get any benefit out of them. By then you will have an old dishwasher that you have paid a lot for extended warranties on. So do the math.

In my opinion:

Simple is best. I wouldn't spend $1,000 for a dishwasher with all the unnessesary bells and whistles. Just a simple dishwasher with an ordinary mechanical timer works fine.

When your warranty does run out, and it has a problem, it is easier to diagnose and parts are cheaper.

Remember, the $1,000 dishwaser and the $250 dishwasher perform the same task:
Pump hot water over dishes to clean. Get one with a pots and pans or "heavy" cycle.

The cheap one might not tell you "good morning" when you enter the room, but you won't be in here asking about what a E5 code means either..