It'll be a dual boiler type anyway I think,
looked at heat exchanger units, swings and roundabouts, but like the idea of fast heat up in the morning, and no messing about waiting for steam to get up to pressure.
Those E61 grouphead Italian machines DO look nice though, I like the old school, hands on "Flood the Engine room" look they have. 
One of the machines I looked last time I was shopping at was the Rocket Appartamento, but hitting the coffee forums recently its not quite as big a deal as it was a couple of years ago, when I last looked at these.
Got a mokka pot instead to see if I had the level of "arsedness" to go down the espresso route.
Grinding beans n stuff, and its absolutely worth it.
Convenience, flexibility and consistency is what I'm looking at.
Low maintenance is a factor too, I know these aren't plug n play, but some need more faff than others, the Heat Exchangers in particular it seems to me.
So dual boiler it is.
Ok with not having it on Betamax nowadays