Same brand appliances appear more 'high-end' to potential renters.

Stainless steel appears "high end" regardless of brand. Yes, you can combine appliance brands. Not sure of the pricing but since this is a rental, pay particular attention to the appliance warranty's and go for the ones that are most comprehensive. Renters typically don't care for rental property like an owner would, no matter how "high end."

I agree with Scott Design - check their warranty AND the brand track record for repairs and longevity.