People who rent locally seem to really like Enterprise (as I have when I've used them for replacements while my car was in the shop). But renting at random airports is totally different. I've never even tried Enterprise at airports, since Avis is good enough for me (though that's because I rarely need their customer service, which often isn't that great), and with Avis I can earn tons of airlines miles or hotel points through rich partner bonuses, and I care about that more than customer service. (And last I checked, I can't earn any airline miles or hotel points with Enterprise, let alone rich bonuses on same.)

You can earn National rental credits with most Enterprise locations. Enterprise has its own "rewards" points program, but it's not as versatile as National's, except that National has relatively few neighborhood stores.