This makes it sound like its a breeze and better to buy an older house rather than a new build. You get these problems no matter what you buy, the only choice you have is to understand what you are buying and what the potential risks are (and who is going to try and screw you over in the process)
We bought our first house off plan. It took 6 months longer to build than they initially had said because they screwed up the stairs 3 times (concrete stairs). But we didn't have any issues with snagging. Really good quality, no problems for the entire time we were there bar two lost tiles in gale force winds.
It was in a location we knew well and i knew the historical use of the land and area. Some of the other estates being built at the same time in the area we knew potentially had issues with flooding or subsidence due to their location so we wouldnt touch them (and guess what has happened to those houses. Their value has strangely dipped.)
Fast forward to our new house.
Our solicitor told us our new house was at risk of mining substance and flooding. Which is a bit difficult as its at the top of a hill in an area with no mining history of any kind. And they wouldn't back down.
We ended up having a big argument with them as the stuff they gave us in 'evidence' was a complete shit show. We only kept them as the sale was too far progressed and we'd have lost the house otherwise.
When we moved in we had numerous problems with the house. Far more than we'd ever had with the previous one. But they have been (largely) known quantities and to be expected with the history of the house.
I think for me i take the attitude that you have to take a degree of not taking what you are told at face value and if you are spending hundreds of thousands of pounds on something its wise to research a local area thoroughly yourself for potential historical or topographical issues, as well as employing a (good) solicitor to do land searches. I simply dont trust any of these fuckers anymore.
That said, one of the main reasons we were keen to get off our old estate was due to it being leasehold and there being maintenance charges due to it not being adopted by the local council that we could see becoming an issue in the longer term. We had to pay extra for maintenance of the services and roads (for example we paid for street lighting). We didnt have some of the problems that others who purchased later properties on the estate had as they were on different terms to us, but we could see it still developing as an issue. Theres a ticking financial timebomb on new build properties due to leasehold which so many people buying it dont fully realise because so many mortgage lenders won't issue a mortgage if there is less than 70 years left on the leasehold meaning you cant sell easily unless you pay your way out of the leasehold or extend it even though you own the property the land is on. Its a complete con.
There were definitely shenanigans over it when we bought. When we were sold it by the developer, we were told that it was leasehold for 999 years, then we were told it was leasehold but would revert to freehold on completion of the estate and when the solicitors got the paperwork they discovered that it was 90 years. By this point we'd waited 10 months for it to be built, couldnt afford anything else and were going slightly nuts at my parents so didn't feel we were in a position to argue or walk away. I know that later houses built on the same estate were subject to additional leasehold related charges which increased each year inline with inflation. This increase has seen the monthly charges get to a level which is financially crippling. I know the local MP has been involved over it and other estates in the constituency.
I would never buy leasehold again, because there are too many gremlins hidden in the small print which you dont find out until you get the paperwork in the late stages of purchase if your solicitor is on the ball (i know of people who have only discovered these hidden charges AFTER they've bought). They should be outlawed.