My Sammy is a 3.5 month-old berner pup, and we're working on the housebreaking. He's actually quite good about going outside, in a consistent place, every time I take him. The trick is to take him often, because I'm not at all convinced he really realizes when he has to pee. I take him out FIRST THING after every meal, and every two hours or so outside of that. He has no accidents most days, and he can sleep through the night without peeing in his crate, so if you're not using a crate, that might be a good thing to try as it really seems to work for Sammy.
He does have accidents, though. It's funny, I think he just doesn't quite know when he has to pee, or even when he is peeing! Sometimes (not often, thankfully!) he will actually walk around the house while peeing, dribbling everywhere! Messy! He especially will accidentally pee right after he's eaten, or when he's really excited. I pick him up as soon as I see him go, and take him right outside. Outside, I always praise him for peeing where he is supposed to, and inside, I only reprimand him if I catch him. Even then, maybe sometimes I'm too easy on him, because I think he knows he's SUPPOSED to go outside, but he just can't tell yet when he has to go enough to give me a warning. So I watch him like a hawk, and take him outside a lot!
I'm glad to see someone else with a berner on here! Sammy is my first dog (as an adult, that is), and I am just so proud of him! I think he is the smartest. I'm working on the bell thing with him, but he doesn't get it yet. We'll get there!