The standard seats look like the much-maligned (in the UK) Fainsa Sophia ones, as seen on the 80x for GWR and LNER, all of TPE and Hull Trains' new fleet, and First Class on Thameslink. They're uncomfortable for long journeys but for less than an hour or so I don't have much of an issue with them.
At least the Dutch ones appear to have a low floor for level boarding. British Civities don't even have that!
Correct, they've got Fainsa Sophia seats here as well. The standard class seats are fit for purpose for short journeys, but unfortunately SNG has replaced a significant portion of older stock on peripheral lines. Like Groningen - Zwolle where you'd be sitting on them for more than an hour.
First class seats have a weird bump in the backrest which is at the wrong place, being very uncomfortable.
They do have level boarding, only in first class (which is in the driving trailers) there are steps up to the seats. And due to these steps also many seats facing backwards, so you'd need quite some luck claiming a forward facing seat in first class when a three car unit is the wrong way around. (The 3-car units have only one section 1st, the 4-car units have two mirrored sections 1st)