But if you enjoy 2 things equally (in terms of "feeling"), you can still look what gives you most value for your money. Of course there's a variable of "but if it's more expensive I might enjoy it less" and all, but just in terms of "I like both games equal, how much does it cost me to get in either, how much money does it require for me to keep at it?" that's the price you still can wonder.
I don't think the OP is talking "the fun factor"... it's probably more of a "how can I maximize the fun factor with my money".