I haven't ridden the IRO, but just bought the '10 black Langster last week and couldn't be happier! It's super light-weight and looks pretty cool too. It's my first SS as well and after riding my Specialized Hardrock for the past 4 years and going to this it's insanely fast compared to my MTB (obviously). My vote's for the Langster, although I do have some bias. Good luck with whichever you choose!