I definitely recommend them. All of them. They are not all the same quality, but they are all great games, the best superhero games so far by far.
Asylum is the first, and while a bit awkward in some aspects, it clearly shows why the series became so iconic.
City is the best, the story grows so much, much more Super-heroy and like a Comic, which I love. Very very good.
Origin is unnecessary, but good. It is there. It is fun, and a great game on general, but kind of just is there in the seires.
Knight is good too, but I expected more. I love the ending, but they really overdid with the damn batmobile.