This question may not be appropriate for this board.
I'm a physics major, and I have gotten two fairly prestegious internships - one at a national lab, and one at probably the best school in my field of physics.
The good thing about going to a national lab is the fact that they have a very good retention rate for interns. I don't have the exact numbers but its ~3/4. The pay is very good, and they sometimes pay for your grad school, if you continue working with them.
The internship with the university gives me the opportunity to work with my first choice for a PhD advisor. Pays for food, lodging, and gives a nice stipend. Factoring all of this in, the amount of money I'd have at the end of the summer would be essentially the same for both cases.
Which one of the options do you guys think would be best for me in the long run?
Pick the safe route. You know your options better than we do. Pick whatever is safest. If it has a good retention rate, go for it.
1 bird in hand is better than 2 birds in the bush.
this is the time for you to stop being a smart guy and go with your heart
I would go with the first, but it's ultimately up to you.
Shit I can barely think 2 days ahead I can only imagine what you got prepared for yourself good luck man