Some observations from Belgium :-
Level boarding is much better in the UK. Here the platform, often just gravel can be very low.
Passenger assistance is very good in the UK compared to here.
Service frequency is generally much better in the UK.
Last trains run much later. Cost me many a taxi to get home from a concert in Brussels as the last train would be around 11:30.
Most big stations have a book shop, pub, something decent to eat. More like airports than railway stations. St P. being the best.
Catering on board the train. Unheard of here on domestic services.
On the down side :-
Walk up tickets are very expensive in the UK. Last time I did Paddington-Bridgend it was 106 pounds for an open return. (was an emergency as my Dad was about to die).
You can't buy beer from vending machines