I've had both. 2 goldens and now 4 labs.
They are different, but are both bred to have similar temperaments and instincts. Exercise needs are broadly similar.
IMO, a Golden is a bit more demanding than a Labrador, and slightly harder to train. A well known theory is that in the time it takes to train 1 Flatcoat, you can train 2 goldens and 4 Labradors.
A new puppy is very hard work and will dominate your every moment, pretty much, for a couple of months. I think it's a bit like having a newborn toddler tbh. They haven't a clue what's right or wrong, don't understand what you want but can run around the house at a billion miles an hour, wail like a banshee, wee and poo more often that you'd think was possible and can get into trouble or hurt themselves in a flash.
Puppies need to learn to be left alone, so you start with a tiny time and build up slowly. School runs and shopping trips will be no problem in the end, but to start with I always start a little at a time. I don't leave mine for more than 4 hours max.
As any good breeder will have a waiting list for puppies (don't think about buying from a breeder who doesn't - partic with these breeds, and don't forget the health tests you need to check out).
Grooming requirements are more demanding for a golden than a lab - the feathers can bring in a lot of mud and pick up burrs.
I'd strongly suggest you spend some time with both breeds to see which you really like the most; it's a big commitment and choosing just on look is not the best idea tbh.