IMHO PTv1 is much more practical. If you see a bus or a bus stop on a road then you know you can add it to the relation and the whole route will gradually get completed over time.
With 'v2 you have to guess which of the (at least) two different relations you need to add it to unless you can get close enough to the stop to read the tiny text on the timetable (if it even has one), so you can't even do both sides of the road at once.