OK, so if it's going in local to you (Adelaide), water quality is going to be the major challenge. Some manufacturers of equipment are getting to the point of restricting or limiting their warranties to just Melbourne & Sydney metro areas.....which is more than a little insulting for the rest of Oz. Sometimes these limitations are in the unnoticed fine print and typically only get **tested** when something goes wrong before the 12 month period.
Copper boiler machines from the medium or lower-range equipment are half the price and depending on the circumstances can last twice as long (in extreme water areas) - of course those are some big statements, but it's based on a decade of observations. It's a reason most mobile coffee operators don't use Blingy-Blingy brand equipment.
The San Remo Opera is the current "must-have" bling and not just because it looks good - might tasty shots emit from this amazing machine.
Personally, I'd be steering clear of Slayer and Synesso for controversial reasons I won't publish publicly. Worked with customers that have the many scars. As with all equipment, things do get better as they evolve and incrementally eliminate gremlins with each new year and model, but it's a steep $$ slope. There is no denying that those premium brands produce exception coffee in the hands of the skilled, as do the LM's, but it's coming at a price premium.
There has been no remit on the objective for this equipment, so one can only assume it's a cafe.
Cafes are in the business of trying to make money, which is not easy these days.
For the last 5 years, the stylistic agenda for cafes has been utterly hijacked by obsessive fears of supposed brand snobbishness. That is, unless you have a LM/SYN/SLAY branded machine, you just aren't serious about coffee and cafe owners suffer from exaggerated imaginations that every customer can tell the difference upon split-second eyeballing the equipment when they poke their head into the entrance - which we all know is nonsense. Less than 1% of their customers would know the difference in branded equipment and generally those are rarely going to become your "regulars".
When you decide you must have a LM/SLAY/SYN, it's for reasons that are purist. You want the very best coffee and you believe it's essential or fundamental to that pursuit. It's not going to result in a point of difference because anyone can install a similar machine. Just like buying cars, you can generally tell the difference between the Commodore and the E-Series Merc across a number of aspects.
Will the **look** attract more customers - unlikely. Will it result in an improved ROI over a defined period - nope. Will it make the barista's life easier, more productive ? hardly.
Better trained staff and a great culture always generate superior results over the "geeky equipment philes".
Some of the best machines for cafe duty have never featured in the top 3 aspiration list - BFC Synchro (no longer imported) and Nouva Simonelli T3 Aurelia are both examples of delightful machines to use (for the Barista) and superb cup outcomes.
Ash, your friend needs to arrive at a set of clear objectives when identifying the ideal machine. Google is not going to help because there is too much noise and eye-candy.
Hit up some cafes with the short-listed equipment and try to get some honest, real, anecdotal feedback - you might be surprised at how many "dramas" occur in real life.