GPS is the only way in my book. They are accurate to a few yards, which is close enough for all but the very best golfers and can give you a yardage even if you are over a hill and 2 fairways over (just in case) and you cannot see the target. Same for an elevated green, where you cannot see the flag, it gives you what you need.
My GPS is old. Like 12 or more years old, uses 3 AAA batteries that last about 5 rounds and it holds 20 courses (you download them for free). It's a black and white display but gives me what I need and is small.
I agree that lasers are slower. I have a buddy with one and he was always tripping out that I could look at my GPS screen, see middle, front and back locations, and just look at the flag and have the yardage within 2 yards, all before he was done shooting the target.