I say rings all the way!!! There are so many different exercises you can do with the rings that will hit you like not other exercise, plus you can easily use them off a tree branch too.
Exercises on rings that are awesome:
Breaststroke on Rings
Flys on Rings
And so many more. How much are you looking to buy your rings for?? I got mine for about $70 which when you find all the different exercises you can do without a gym it is well worth the cost!!