The crime rate in Pottstown is actually worse than Norristown if you look at the data. Violent crime is 1 in 128 vs 1 in 216, property is 1 in 32 vs 1 in 60. Crime has also slowly been trending down in Norristown while still worse than most of the rest of the county.

I have friends in both and the basic vibe I get is that Norristown kind of has a baseline level and then some areas are much worse (especially down around Markley) whereas Pottstown is kind of pockets of good and pockets of complete shit.