After over 1300 games of Challengers and 100 games of Challengers Beach Cup, I must say that beach cup is better for 2 reasons: it's much more balanced and much less luck reliant. There are many possible combos and strategies, many ways to come back when losing, (even on last round) and more options when deckbuilding each round. Also, having a deck made of the same set it's not as opressive. Current season has trainers, wich I didn't like at first, but then I realised that they increased the skill ceiling even more.
On the other hand, in Challengers 1, If you are at higher ranks, you have to get one of the meta strategies (such as 2 vendors, UFO, sailors, etc) at the very beggining, or else you are cooked. Beach Cup doesn't have that that problem, as every strategy has many counters available.
Bonus: Beach Cup has better initial rounds, as dog has a deck manipulation ability and you get 3 cards from deck A on round 1.
On the other hand, in Challengers 1, If you are at higher ranks, you have to get one of the meta strategies (such as 2 vendors, UFO, sailors, etc) at the very beggining, or else you are cooked. Beach Cup doesn't have that that problem, as every strategy has many counters available.
Bonus: Beach Cup has better initial rounds, as dog has a deck manipulation ability and you get 3 cards from deck A on round 1.