Hello; I have the opportunity to set up a close friend with a machine and grinder (and all the rest). The budget is good and I am considering even a GS3 or Cimbali Jr. or a Classe 6 and a Mazzer Mini or Macap. She knows this is a big deal and will require learning and practice to get it right. Would I be correct in thinking that a double boiler type machine will be easier to learn? She is a serious cook so I don't think this is a hard road going nowhere but I want to make it less of a slog to get proper coffee. Any ideas on beans for this situation?
Thanks, KDM

There's ample debate of the merits of the two types of boiler designs. Below is a sample of the more thorough discussions of the topic:

• HX vs DB
• HX vs double boiler in the real world
• The Worst Thing about HX Machines/Heat Exchangers are evil
• Why are HX espresso machines so popular?
• Some thoughts on heat exchanger vs. double boiler espresso machines
• Why not double boiler with PID?

To your questions:

Yes, the temperature management of double boilers is unquestionably easier. Beyond this rather obvious observation, one must compare the performance/qualities of a specific espresso machine against another. Comparisons based purely on spec sheets (e.g., boiler design, group design, features) will lead to a superficial decision. When taking into the account the various recommendations you're sure to receive, there's no more valuable piece of advice than this: There's no substitute for hands-on experience.

As for coffees, that's not really specific to the machine type and there are ample threads with recommendations in the Coffees forum.

Keith -- if you (and friend) want to check out my machine, send me a PM . . .