The Metro is really no worse than any other urban public transport system. You get the kids on stinking of pot and shouting and swearing, and the odd missile lobbed at a train, but nothing you don't see in Manchester, Liverpool or London.
There are specific stations I wouldn't use at night- Pelaw and Gateshead Stadium south of the river, Meadowell in North Tyneside- but not on the airport branch and it won't be an issue if you're just going to/from the airport.
I’d say it’s worse than London Underground. What you don’t generally get on TFL is a station which is essentially right in the middle of an estate, unstaffed, and nothing to stop people entering the system without paying. So it does allow undesirable types to roam largely at their own devices, unfortunately Tyneside and Wearside are no different to any other urban areas in having a proportion of such types. This also means it’s the chosen means for teenagers to get around, which to be fair in most cases isn’t really a problem, but again like anywhere there are going to be issues when they congregate in groups. There seem to be a few stations which act as de-facto teenager hangouts in the evening, Pelaw is certainly one, there’s a few others too. One doesn’t really see this in London.
I certainly have felt mildly uncomfortable at times on the Metro, and not just at night time, and this is from someone who’s used to London. Smashed windows is also pretty common; when we were staying in Tynemouth earlier this year and using the metro daily it was very common to see trains withdrawn from service due to smashed windows, or drivers checking their train having heard a bang, quite depressing really.
We’ve before had a list of sections posted on here which are particularly rough, which amounts to a good proportion of the system. Something along the lines of
* Byker to North Shields with special mention for Meadow Well (Smith’s Park).
* The coast during school holidays
* Shiremoor
* Regent Centre to Fawdon
* Gateshead Stadium to South Shields, especially Gateshead Stadium, Felling, Pelaw, Tyne Dock and Chichester
* Fellgate and Seaburn
* Park Lane to South Hylton
This must be about 75% of the system, and basically leaves the central area, the bit around Jesmond/Gosforth, the top side of the coast loop, and the north western tip of the Airport branch.