The exceptional goaltender part is too early to claim. Andersen has been an average or slightly above average goaltender in terms of save percentage and adjusted save percentage thus far in his career. He has not been exceptional.
He may very well end up at that level and has plenty of time to grow as he's played less than 200 NHL games but we can't get too ahead of ourselves here.
For the question at hand, Andersen is the guy to own today but that could certainly change in a couple of seasons. I like Hellebuyck's skill set a lot more than Andersen's but Freddie is in a far better situation with that trade and new contract. Winnipeg appears to be taking the slow-cook approach with Helle so the wait time will obviously be longer.