Anything stocked at HN is probably not a machine to buy.
Read a few reviews and threads on the coffeesnobs website - But don’t get sucked into thinking “for only $X more I could have Y awesome machine that will make god-shots from vittoria pregound”. Skill, grind, and fresh beans are more important than ECM vs Isomac vs Diadema vs Rancilio.
As Ben said second hand is good (check coffeesnobs, Ebay, greys online, gumtree). But you won’t likely get any warranty. This is ok with most machines because there’s very little that can’t be fixed on a decent 1 group machine by a good service and repair joint. Factor in a service if you buy second hand. They should clean, descale, and check the pressure/temp of the machine is within normal specs.
Read up on whether you want single boiler (one boiler for steam with the brew water coming through a HX) or double boiler (one for brewing, one for steam).
Depending on your budget - Keep some cash in reserve to buy other coffee toys. A cheap pourover setup for filter coffees, an aeropress, a chemex, a roaster?
my old man has a promac one, i think it’s about as big as you can get without needing to be plumbed in permanently. (i think it’s the “Club PU/S” from looking at their website)
i have no idea what it cost but he’s a bit of a snob and is very happy with it. i think they are rebadged rancilios.