There are three town centres of which I have very recent experience, including some bus services:

Nailsea.
I needed to travel into Bristol early on Monday morning for a medical appointment at the BRI (yes, bobm, I know that is also the correct station code for Bristol Temple Meads ). The X9 service took me promptly from the centre of Nailsea to Bristol Bus Station in about 40 minutes - no problem. It was then only a brief stroll up to the hospital.  The return journey didn't go quite so smoothly - the X9 service on bay 14 in Marlborough Street bus station was notable for its absence, so I chose to stroll down to BRI (Bristol Temple Meads railway station ), pausing only to refresh myself in a couple of Wetherspoons on route.
The town centre in Nailsea has also seen some decline, over the years. We have lost all of our bank branches and many traditional family shop businesses. The pubs generally remain - including a new Micropub - but it seems that every other shopfront now is either a charity shop or a Turkish barbers.

Melksham.
During my recent visits to Melksham, I twice used the bus to travel from the centre of the town into the centre of Bath - Manvers Street, by the railway station. Excellent scenic (for me, as a visitor) journey on both occasions - and all for £3.
I found the centre of Melksham to be fairly lively - in a good way. Road traffic is quite heavy, but there are plenty of pedestrian crossings. There is a wide variety of shops, including some fascinating antique / collectibles. Also, there is a good selection of pubs, including an excellent Wetherspoons - The Bear.  However, once you go beyond The Bear towards the railway station, the amount of derelict commercial and industrial premises is rather depressing.

Swindon.
I have no experience of the bus services in Swindon - never had occasion to require them.
A few weeks ago, walking from Milford House (the head office of GWR) on Milford Street to the Wetherspoons ('The Sir Daniel') on Fleet Street, I was frankly depressed at the number of boarded up and derelict buildings - contrasting with the almost universal road workings, causing confusion to all pedestrians, as far as I could see. Clearly, money is being spent on public transport (bus lanes, one way systems, etc.) but it was not clear to me quite what facilities would encourage people to actually use them.

That's all from me: I'll hand over now to bobm, a Swindon resident. 

 
The decline of larger town centres has been a popular topic in the media recently. Internet shopping, high car-parking charges, rogue cyclists, beggars and shop-lifters have been blamed, the last three contributing, some people think, to a feeling of unease. I now dislike visiting Reading town centre.

A friend of mine (who cycles around London) reports similar discomfort in London, where the travails of Oxford Street have been commented on.

In contrast I've enjoyed visits to Newbury, Thame, Marlborough and several other smaller towns.

Ironically, Reading Borough Council has recently firmed up its guidance on busking, which is one High Street feature that I do appreciate, sometimes donating money.

 

I agree. I can remember many Saturday afternoons shopping in Slough when I fancied a change from Uxbridge and many evenings I would visit one or several of the towns pubs. Most of the big names have left the High Street and shopping centres, and all of the pubs that I used to frequent are gone too apart from Wetherspoons which I didn't use that often.

The last time I visited, a few months ago, after being depressed by the state that the town centre has become, I wanted a cappuccino before I headed to the station. But where have all the coffee shops gone? I had to do without.

 

.........and yet just a few years ago both of those shopping centres were outstanding, along with many other shops, local facilities and a number of decent pubs in the area, almost all now gone.

Hard to understand how such a once thriving High Street in the wealthy Thames Valley has been allowed to become so run down - Slough Borough Council is incompetent, bankrupt and riddled with whiffs of corruption and must take much of the responsibility, although I think much of the High Street is awaiting redevelopment which it desperately needs.

To be fair, many English towns and (particularly) their High Streets have headed the same way.

 
Bit to late improving connectivity to Slough town centre .....................
Slough High Street and Queensmere Observatory shopping centre are dire possibly the worst town centre in the UK, its dire

 
From the BBC: