Here is a list of the coffee beans by various roasters that we have tested in our espresso maker at home. All coffees are tested as milk drinks; proportions are adjusted for optimal balance.
Hardware:
Expobar Office Lever w/E61 group head
VST18gr basket
Rancilio Rocky grinder
Criteria:
Uniformity: Ease of dialing in the espresso; consistent results.
Flavor: Tastes we experience; enjoyment of the lattes produced.
Balance: Richness and complexity of taste profile; how well espresso and milk combine.