It's my adopted home town - I moved there 30 years ago for partner's work, and never wanted to leave. Although at the moment we have work on the other side of the country. Gorgeous little city - you get the sea breezes, and it's close to the Lake District, Manchester & Leeds. Lovely big old houses in the centre. Two of the best state grammars in the country, and an excellent university.
Yes, it's small, and you will need to get out on occasion, but it's close to so much else, including Scotland - during the Edinburgh Festival, I can go for a day, and see 3 or 4 shows if I plan right.
But it's a small friendly place in the right way - I can go into the pedestrianised town shopping centre on a Saturday morning and always run into someone I know, even when I'm just visiting every second weekend.
It's very safe for children - the kind of place where they can run into town independently. Lots going on in terms of activities.
Thriving arts scene - both at the university and in the town centre - but you'll need to get over any sense of town & gown - the university offers some really fabulous resources for the whole town. Although who knows how it'll be after we're through the current crisis.
If you want all the naff high street shops, you can go to Preston or Manchester (Preston's market is fab).
Really good for foodies - Booths is the local supermarket, and fantastic local produce.
But really, it depends why you're thinking of moving there. I lived in a huge international city before I moved to Lancaster, and found the first year tricky. But I adapted and really miss living there full-time at the moment. I'm done with big cities, and Lancaster has the history and status of the county town of Lancashire - it's a place that's proud of its long history & importance - without the traffic, pollution, and general exhaustion of a big city.