The northern route is the longer of the two routes from Lhasa to Ngari, but there's a reason people put up with the extra travel time. It's the landscapes, the mystical, outsized landscapes, which include huge salt lakes, multicoloured mountains and valleys of semi-nomadic herders. The wildlife is also far richer than along the southern route and you are very likely to see marmots, blue sheep, wild asses, small herds of antelope and lots of yaks.
The entire northern route is now paved and driving conditions are excellent. If you’re travelling this route, seriously consider camping at least once or twice, as the towns are dismal. You need to be well acclimatised if you intend to tackle this route before the rest of Ngari as the road from Raka never really drops below 4500m and is often above 5000m.