When buyers are looking at an upper bracket homes and see the sellers cut corners in any area of the house they start to look at everything more closely wondering where else the seller saved a few bucks. Go with the best brand and have all the appliances match, the appliances set the tone of the kitchen.
They don't want to walk into the Taj Majal (did I spell that right?) and find out that it was outfitted at the local discount store.
Hope that helps!