I’ve ridden AMTRAK several times in the past few years.
I pay for business class, totally worth it, if for nothing more than the extra leg room, but the power outlet and assigned seat make it significantly better.
They are generally on time, generally pleasant. Generally clean. I actually wish we had greater frequency of service out of Norfolk. My daughter was going to school in New Haven, CT, so, Norfolk station, change in DC, Union Station in New Haven. Takes more time than driving, but the cost is about the same and the stress level much, much lower.
She’s going to school in Boston, now, and the same calculus applies - slower than flying, a bit slower than driving, but far lower stress than driving. AMTRAK is a viable alternative.
I used to ride Amtrak fairly often, but as a commute to work if it didn’t feel like driving. But it was mostly a regional service (Capitol Corridor) where the seats were fixed and there’s only one class. Not a whole lot of legroom either.
I have ridden on “long distance” routes. Pretty much only the Coast Starlight, which uses Superliner two-level equipment. Business class there doesn’t necessarily get more comfortable. Regular coach seating on long distance routes is assigned. The seats are large with plenty of legroom. So much legroom that the tray tables have to slide to reach the passenger.
On the regional route they would occasionally use a Superliner cafe car with the cafe on the lower level and those huge seats on the upper level.