It depends on your spending amount and the frequency of united domestic flights. Personally I do not like club credit card because of its huge annual fee. For 1.5 miles per dollar, united explorer card gives you 1.4 miles per dollar for first USD 25000 and the annual fee is 95 with the first year fee waived. And it also gives you two united club passes. I also have business version of united explorer card with same perk and 2 dollar per mile in restaurant.