Personally I find the level of heat on the highest setting to be fine - at least as warm as on my previous BMW, if not higher.
However, it does take a lot longer to get to that level, whereas the BMW heated seats got to top temperature fairly quickly. Also, with the BMW ones, you could vary the split between seat cushion and back and I had it more biased towards my back rather than seat and found that the heat got through a bit quicker. Shame that the VW one doesn't have that feature.