Two machines from the same Breville ThermoJet family, priced about $100 apart. The real decision isn't boiler or portafilter — both are identical — it's auto-tamp versus a finer grind range.
Breville builds both machines on the same ThermoJet boiler and 54mm portafilter, so heat-up speed and aftermarket basket compatibility are identical between them. The difference that actually matters is in the grinder and tamping system: the Impress ships with a 25-setting grinder plus a motorized auto-tamp that applies consistent pressure to the puck, while the Barista Pro skips auto-tamp for a finer 30-setting grind range and a manual tamper.
That trade-off explains most of the ~$100 price gap. You're not paying more for the Barista Pro's grinder because it's better in absolute terms — you're paying for finer adjustment granularity. The Impress's lower price with auto-tamp included is why it scores slightly higher on Match Score despite the coarser grind range: convenience and consistency carry real weight for most home setups.
Yes — both use Breville's ThermoJet system, rated to heat in about 3 seconds, so there's no heat-up speed difference between them.
It gives finer increments between settings, which matters most if you're chasing a precise dial-in for a specific bean. For most users switching between a couple of bags, 25 settings is enough range.
No — auto-tamp is a built-in mechanical feature of the Impress line, not an accessory you can retrofit onto the Barista Pro.