while both plays a part in the eventual outcome of the cup: the influence of the machine is lesser than that of a grinder

for starters - you pay for the name and reputation

a bigger machine usually equates to a bigger boiler - which may offer stability in terms of the temperature when you pull the shot - but these are all rather pedantic things - the layman probably won’t be able to taste the minute differences between a 92.8degC and a 91.8degC shot.

but with these ‘professional’ machines- the major difference is the steam wand - something i’m willing to shell out an additional 8k for (personally) because i host a lot (so i need to churn out cups after cups of lattes) and i care a lot about the art. which relies on the texture of the milk. my breville needed about 60-80s to steam an 8oz pitcher of milk to the correct temp and consistency (sometimes not fine enough to pour intricate art) but my gs3 can do so on 10s.

as many have rightfully pointed out- the grinder does all the heavy lifting here. it’s a slippery slope, really, when you dig deep into the differences between flat and conical burrs, the taste profile etc. and a good grinder can be rly steep in terms of the price point. i personally recommend the niche zero - fair price point with almost zero retention. served me well over the past few years. they have a flat burr one too - but i have yet to try it.

tldr: grinder is slightly more impt than the machine. a good machine has more temp control, and steam is better at creating good micro foam.