I definitely suggest both!
A license will give you access to the MLS for comps and other great benefits, and you can always have that hat to wear if you need it. For instance if you meet a seller who really is more of a listing than an investment type deal, bam! You're an agent that can list it for them and collect that commision.
Most of the (big) investors in NJ that I know started out with getting licenses due to the many benefits. I have been investing for years now and I recently started a course to get my license, I wish I did it sooner.
In regards to being a realtor or investor, I say be an investor with a license for a good 1-2 punch so you can approach sellers with all options under your belt! Its also great that you already have the contractor part of it down.
Come out to the meetups and you'll learn a ton and can make a better decision and learn from more people, all I've said is from my opinion and what I've experienced/learned....our company just spoke at Chris Goodsons event last night. Theres NJRESN, NJREIA, and NJREIC. Tons of investors/realtors/attorneys under one roof learning and networking.