Definitely getting both for a lot of reasons actually. For one, it'll be a plus to have both as it'll make getting all the starters easier and plus when I need to trade for an evolution that I need I can do it simply easy and faster than through Wi-Fi where you can get a little lag during the process. Also, getting both only means double the fun, and if I gain somethign rare and exclusive at least I have a backup where I won't lose it when needed. Even if I get bored, I've got one to play over just for nostalgic reasons. And having the chance to relive Johto with the new style they've given it will be quite fun, and not to mention all the features that'll be included.
I've got to say, I never got to play Gold before neither Silver, only Crystal. Having the chance to see what it might have been like compared to Crystal would be a great experience to share. Having both will also allow me to easily get the exclusives from each generation, like how I was able to do back in RSE, FRLG, and now DPPt.
Twice the fun, and twice the trouble when it comes to Team Rocket as well.