Sometimes, due to the variable pricing, a 1st class Thalys ticket can be as cheap as a 2nd class ticket. My wife and I traveled 1st class from Amsterdam to Paris, which was extremely comfortable, and came with free wifi, food and drink, and probably some other luxuries.
The return trip was 2nd class, which meant you had to pay extra for wifi (despite many Dutch intercity trains having free wifi these days), and lacked the free food and drink.
Not sure if it was cramped. Still better than a plane, as far as I recall.
But next time, we'll definitely be looking out for cheap 1st class tickets.
Well Thalys trains were made in 1995-6 and it shows. They actually have comparable leg room as airplanes (at least with legacy carriers)