It really comes down to what you ultimately want to do with your photos....how much processing you'd be comfortable with. I have both and they both work great...for what they do. NX2 even comes with a little booklet showing you step by step for each process you want to work with and what it does. Lightroom is, of course, a lot more advanced and does considerably more in the way of processing. If you're good with a learning curve, go for Lightroom. If you just want to do light processing and touchups and such, go for NX2. Also, it comes down to your wallet, too. Which one can you most afford right now?

Personally, I feel if you started with NX2, you'll get a feel for what you can do with it, and it will give you the incentive to move up to the more powerful Lightroom in the future, should you be so inclined.

Good luck with your choice.