My first choice would be local warranties & installation, then years from now consider some replacements to come from the discount outlets.
Installation of non-gas appliances can be simple, once a side-hussle for a local preacher in-the-day.
Gas appliances may not need a plumber but gas goes bang and is not simply plugNplay, so plumber for me.
Warranties are builder supplier all about except appliances. The units are covered by the manufacturer but the locale can suffer from less pampering, so a local would have to pick up the caring you deserve.
National home warranties can guard you with the cheapest, lowest rated guys in town that may give up after several failed repair trips.
If 30-40% savings is that important, perhaps shop cheaper local appliances to serve the new house for the initial years, then if you don't flip it, it becomes a forever house, then upgrade some appliances.
Short-hand answers here ... long-hand help here ....
http://pages.suddenlink.net/tgivaughn/