I see no reason to match manufacturers of your appliances.

Best quality is good if they have the features you will really use. We went with different brands for the fridge and cooktop, but went with one brand for the wall ovens, microwave and dishwasher (Bosch), because the brand was reputable and because of the discount for purchasing 3 or more of the brand (microwave was basically free). I think unless you're saving a bundle or really really like the brand, there's no other reason to go with matching appliances (same brand or same line).

Thanks for the feedback. Do you think the differences in handles or variation of stainless makes any difference?

We have a home inspection division with our company, and just from experience we're finding that the brand with the most features, style, and reliability, keep in mind this changes every few years, but right now: GE monogram seems to be at the top the charts.

I can't see any variation in stainless finishes with what we got. I think they are pretty consistent, even matches our stainless faucets and cab hardware. The different door handles may make a difference if they're right next to each other, but the style difference would have to be profound. The different handles on our wall ovens and fridge don't register to me.