Got one now. Does not need a lot of exercise at all! Ours is a right lazy bugger. Get a five min walk first thing in the morning, half hour to forty five minutes at about 5.30, and another 5 minutes at about 10pm. She gets taken out by dh for the odd 2-3 mile run and looks very affronted by the whole thing.
Very easy to train - smart enough to train, not smart enough to try to outwit you.
Ours really wasn't that mouthy as a pup, she chewed the corner of one wicker sofa, but it was in her 'room' and in fairness, it was made of sticks.
Ours doesn't have much of an instinct to retrieve as it happens, but she does like to carry soft toys around. Never had any issue with her taking dds toys though, she seems to just get which ones are hers.
Lovely family pet - docile, fab with kids, cuddly, obedient. But the fur! They shed all year round, and you can't have them clipped because it screws up their temperature regulation. So make sure you can cope with living in a furry house!