I have two IGH bikes, a SA 8 on a MBT frame and a Shimano 11 on a commuter road bike. I also have two external derailluer bikes. The IGH bikes are heavy in comparison. Slow from a stop.

The 8 speed has gaps (between gears) that are noticble, the 11 isn't really noticable in that way. The 8speed hates to be shifted while pedaling and the grease inside gets sluggish in the cold. The 11 speed is very forgiving when pedaling while shifting and I haven't noticed any difference in cold weather (oil lubricated).

It's nice to be able to shift when stopped, but. The only real reason I feel most (commuters have such disparite rides compared to other riders) commuters should consider an IGH over an external derailluer bike is if they are riding all year long in all types of weather, even then they should seriously think about the weight penalty as it changes the bikes ride a great deal.