Saffron Walden is beautiful, but you would need to cycle or drive to Audley End station for the train, and the journey is a bit further and the trains less frequent (Stortford has both the Stansted and Cambridge trains stopping there). I’d personally only consider Saffron Walden if commuting was likely to be once or twice a week.
For schools, I think there is a wider choice in Stortford: the general view here is that all the primaries are good, and there are 5 state secondaries (all-boys, all-girls, Catholic, mixed comprehensive and mixed selective). The “best” schools are perceived to be the selective and single-sex schools so if you have strong views about single-sex education, you might want to do more research.
Pressure on school places: I don’t know anyone who didn’t get their first choice school for reception entry last year so I’m not sure this has had a huge impact yet. There is a new school being built, I think. In-year entry is more problematic but places are available and do come up, especially in surrounding village schools.
As to the previous more negative comments about Stortford: it is true that the town is bigger now, traffic is more of an issue and there is more pressure on health services and leisure facilities, which haven’t necessarily kept up with the pace of housing development. But the pressure on public services is nothing like in London.
There is crime and anti-social behaviour but personally we’ve never had an issue and we’ve been here almost 4 years. I’m aware of a couple of burglaries locally and one of my neighbours had an attempted car theft. But again, that happens everywhere.