As you point out it's a very personal choice in terms of style and details, Your other point boils down to what good or bad in terms of reliability. With the exception of one or two specific model related issues (i.e. cracks in end panels etc) there is little to choose between UK manufacturers, and sadly that means none stand out in terms of statistically providing more reliable products than the others.
Manufacturers believe they have good product designs, which can't be argued because some of their production does indeed work perfectly and do not require any warrantable repairs, The problem is their production techniques do not consistently produce fault free products. Consecutive vans from a production line may have chalk and cheese reliability. This shoots holes in their claims of operating effective Quality Assurance or Quality Control systems - If they have any form of quality system it is ineffective!
The Consumer Rights Act is based on the premise that every retail customer has the inalienable
right to expect products they contract to purchase should be perfect in every respect. If they're not then the retailer has failed in their legal duty to supply fault free goods. But sadly the UK Caravan industry has historically got away with failing to to consistently provide good products from new, and the buying public have become accustomed to receiving caravans that have faults and don't complain when they have the right to and should complain. This fails to send the right messages to the industry so they continue to operate inadequate control systems. Don't take the side of the Dealer if they describe a manufacturing fault , as they have failed in their duty to check the goods before selling them to you!
The historic unreliability means regardless of the make or model, you may be lucky and get a great fully functioning caravan from new, but you have an equal chance of getting one that has problems or may be a lemon.
I must put this into some sort of perspective:- Forums will be biased towards reporting problems. It is Human nature to only make a song and dance about a product when it doesn't perform as expected, Generally that means a properly functioning product won't elicit a public response, but produce a faulty one and its open season to berate it and to report your experience. But that can work both ways, if you receive exceptional service, some people are moved to make it known.
Regardless of make or model you have a roughly equal chance of receiving a good bad or ugly caravan As it seems you are looking at secondhand caravans, there is a better chance the original owner may have experienced most of the problems and put them right.
Just choose the model that provides the layout and style you want.