First impressions - wall of text follows:
First, this scale is not comparable an Acaia scale. Acaia scales are MUCH more expensive. OTOH, the Brewista is around double the price of an AWS 2kg, and has similar specs to the AWS.
There are lots of YT videos and more added as the scale becomes more widely available in North America, so I won't bother posting mine. Brewista also has a nice YouTube video that explains everything about the modes.
The scale was introduced in the UK (Europe?) before it came to North America. Thus, UK coffee forums have more info, but the info may be out of date. The firmware has changed from the UK intro models.
Size is identical to the AWS 2kg. The two plastic weigh covers are the same size as the AWS (or Smartweigh, or ...).
The scales measurements react (change) with heat. An insulating pad is needed - I cut up an old mouse pad.
Display (black on orange) is large and easy to read, much easier than the black on blue AWS or SmartWeigh displays.
Auto turn-off is user-configurable to one, two, or three minutes, or disabled. Those of you with the non-AC-powered AWS will appreciate this.
There are two main reasons I wanted this scale, even though I have an AWS 2kg: water resistance and "smarts." Smarts I will divide into espresso and pour-over.
The scale is water resistant. However, it isn't rated IP65. UK forums show some evidence of leaking into the battery compartment. In mine, there are visible wires in between the top of the base of the scale and the measurement surface. Thus, I won't be rinsing mine under a tap, even if that's what they say can be done.
(If you have an AWS, clear packing tape over the button/display area is a quick and effective mod for misplaced drips/naked PF channeling. More protection can be had by putting the small weigh cover on the scale inverted (like a bowl) and then placing the bigger weigh cover over the scale/small cover (you have to tare first, of course). Even more protection can be had by putting the scale in a ziplock, or sealing the scale in a plastic bag with a food vacuum thing (don't apply vacuum, just seal).)
"Smarts" for espresso are well-done, and work reasonably well. To me, it felt like a lot of work went into calibrating the modes, especially mode 4.
Auto1: cup on scale, time/weight tare automatically, and timer starts counting up.
Auto2: cup on scale, time/weight tare automatically, (manually) press timer button to start timer.
Auto3: cup on scale, weight tares automatically. Timer does SFA.
Auto4: cup on scale, time/weight tare automatically. After about a second's worth of espresso drops, the timer and scale will start (and show time & weight from back a second and a bit).
The real-time-ness of the scale is not super-amazing, but it isn't super-slow, either. Perhaps - perhaps - slightly better than the AWS 2kg.
In all modes, lifting the cup freezes the display. You have five seconds after the display freezes to read the scale - after five seconds, the scale/time resets to zero. I felt that the reset to zero made sense for pros working bar, but not so much for home users. Brew Global may make the reset time adjustable or disable-a-ble in a future release. There does not appear to be a facility to update the firmware post-purchase.
The key point is you MUST end extraction by lifting the cup. Anything else, like sliding the cup, can confuse the scale. This is why I had a hard time assessing whether the scale was better or worse than the AWS for reaction times - I was/am used to sliding the AWS.
As long as I was grinding for a reasonably normal extraction time for a double espresso into a single cup, everything worked as advertised. Running outside these parameters occasionally confused the scale, but I expected this. I did my testing with the Strega and auto4 mode, and lifting the cup worked to freeze the scale/timer, even with the runoff continuing to pour onto the scale. After a week, I was still not used to seeing that, though!
"Smarts" for pour-over were, to be blunt, dumb. There are two modes, one is full manual. The other is: place brewer on scale, scale auto-tares. Add coffee, scale auto-tares once weight is stable for three seconds. Add water, timer and scale start. Remove brewer, and time/weight freezes and displays for five seconds, and then resets.
Sounds good, eh? Well ... I tested with a V60. First, if you fool about with the coffee bed, like tap to settle, the scale gets confused. There will be a new mode in a future release to address this issue according to Brewista. The other issue is how the scale defines removing the brewer (stopping rule). It appears to define it as a reduction in mass - but, unfortunately, any reported reduction in mass. Thus, as long as you pour, you're okay. Stir the grounds/scrape the high-and-dry grounds, the scale resets - sometimes. Touch the kettle's spout on your V60, the scale resets - sometimes. Touch your V60 or mug/carafe while pouring, the scale resets - sometimes. Pulse pour, the scale resets - sometimes. It took me a week to figure it out, and then I confirmed my suspicions with Brewista.
The solution (for V60), is to use a pourover stand, and then the espresso modes - auto2, for example, will work. There are some nice stands on Etsy ...