https://www.mlb.com/nationals/fans/commitmentNoteworthy items:
-monthly “value days” with reduced admission and concessions (I’d guess it should just select concessions)
-concessions guarantee: if they run out of your item, you get a coupon for future use
-pre-load eCash onto your ticket for a 15% concession discount
And most notable:
Weather Guarantee (Old guarantee, still in place): If a game is postponed due to weather, any ticket purchased through nationals.com may be exchanged for a future game - whether you attended the game or not
*New for 2018* - If a game is delayed prior to the sixth inning for more than an hour due to weather, fans attending the game may exchange tickets purchased through nationals.com for a future game at the Nationals Park Box Office on the night of the game
*New for 2018* - If a game is delayed before the sixth inning for more than an hour due to weather, fans who did not attend the game may exchange tickets purchased through nationals.com for a future game, from a select list of available games
All these goodies apply to tickets you buy from nationals.com, so for SPH the biggest new goody is that weather guarantee and I gotta say, I like that one a whole lot.