Seems to me that it's all a matter of torque, and how the curve is set. As I said, it's a while ago, but I felt that the van didn't start pulling properly until 2,200rpm - i.e. 75 mph (indicated), and just got sweeter (and more illegal!), thereafter.
My Missus always used to say it was 'groaning' if I tried to accelerate at any lower revs., and grumble at me!
Mind you, the setting on ALL 'gear change alerts' are now impossibly low, way below the revs we think are needed - so we ignore them completely.
On the last van we tested, (a MAN -i.e. Crafter automatic), takeoff was dreadfully slow on roundabouts, as it was in 3rd by 15mph!
The 102, 5-speed, however, always seems to be perfectly and intuitively geared, if a little limited in top speed. But unless lowered with tweaked shockers etc , no Transporter is as chuckable on bendy roads as, say, a Trannie Custom, so has to be driven with a little more caution. Especially if it's a camper!
I do like my 204, and straight line performance is phenomenal, but a 102 would be perfectly acceptable (to me), and it's cross-country speed is much the same.