Chelmsford is a nice place to live. I moved from Cambridge (much against my better judgement, but I was in love and wanted to work in London!) 10 years ago, and we bought last year. I'd still rather live in Cambridge but can't afford it, sadly!
It's vastly improved since it gained city status in 2012. There's a new shopping area with a John Lewis and lots of naice shops (White Stuff, Cath Kidston, Hotel Chocolat) and restaurants, and masses of housing being built on the outskirts. There's meant to be a second station being built at Beaulieu, but it's been promised for 20 years so may not materialise.
The people are generic, with scales riding somewhere between Towie and rich farmer. There's a general feeling that Chelmsford is a small market town with ideas above its station, but that's mainly from the older people who don't like change. It was a bit of a shock coming from hippie, touristy Cambridge and to be honest I still haven't adjusted, but it's fine really. Politically it's very Tory. The MP is responsive but toes the party line. He's retiring next election.
Pros - improving town, lots of lovely countryside nearby, decent schools, parks, nearish London.
Cons - can get very busy, not much cultural stuff (though it is getting better), not exactly a pretty town.
Looking at the map I'd suggest you check the actual commute before moving, as the roads are busy and you might prefer to be closer to Tilbury.