Is there much difference between Cheltenham and Gloucester? I can't get my head around the price of houses there. My house is tiny in comparison and cost twice as much. I might move!
I think 30 years ago, there was a "massive" difference, now I'm not so sure. I'll try and give a balanced view.
If you compare what I'd class as the absolute best areas of Cheltenham (Montpellier, Landsdown, Charlton Kings, Leckhampton) to the absolute worst areas of Gloucester, then yes, its vastly different. However, I'm pretty sure Montpellier is in the top 10 most expensive and desirable places to live in the UK. (I'd loop places like Tivoli, The Park, The Suffolks, etc into Montpellier). Have a read of this to see how its, fairly, compared to Bath and Oxford
https://www.ft.com/content/a7435730-0c99-11e6-b41f-0beb7e589515
The other thing which always drags a comparison is schooling. Cheltenham has arguably some of the best private schools in the country (Cheltenham Boys College, Cheltenham Girls College, Dean Close, St Edwards), and these are compared the the very worst secondary schools in Gloucester, most of which have now gone and turned into new acadamy sites.
Gloucester has a handful of private Schools (Notably Kings, which featured in the Harry Potter films along with the Cathedral) but I'd say that state schools are far more comparable (Gloucester has I believe 4 Grammar schools (Crypt, Sir Tommy Rich's, Ribston High, School for Girls) and Cheltenham has one (Pates, which to be fair has a huge catchment pull). You then have Marling and Stroud High School for Girls, both just on the edge of south Gloucester. State school wise Chosen Hill and Balcaras always used to be the best. Chosen Hill in Churchdown (a 'village' between Cheltenham and Gloucester) which at one point was in the top 5 comprehensive schools for results in the county).
Cheltenham however is like any part of the world, there are good and bad areas. The bad areas are just like the bad area in any area. Gloucester has had significant investment now, and locations like the Quays are now very nice. The City centre is finally being invested in and previously it was, well, not great.
In my opinion has vastly closed the gap. I too have lived in Cheltenham & Gloucester since the late 1980's.
I think ultimately, Gloucester is 'just a normal place to live' and Cheltenham always has its absolute best areas used as a comparison to it. IMO the price gap isn't at all justified. Thats why established suburbs in Gloucester like Longlevens and Abbeymead have seen huge price increases over the last 10-15 years.