Hi,

As you have started to find out these machines have lots of electronics issues. However, they also have mechanical issues that are less known.

Yes, they have ball-screws but how the ball-screws are connected to the machine is poor which defeats the point of ball-screws.
They mount them using non-angular contact bearings which are machined into the endplates(poorly) and allow the ball-screw to float. Which results in back-lash.
(Look closely at the pics and you'll see the bearings and single ordinary nut sticking thru gantry sides.)

There are other less than ideal design features like how the gantry flimsily fastens to bearings but they are not so much a problem as the ball-screws.

That said for occasional use in soft materials and learning these machines are Ok. But if you want high accuracy in harder materials like brass and prolong use then I'd give them a miss.

Unfortunately, while many low priced kits etc exist, none of them are any good or what I'd recommend to anyone wanting to cut anything harder than balsa wood or whipped cream.

Bottom line is that there isn't any machine out there at low price that is any good and thats simply because it's not financially possible. The only way you can have a Good and accurate machine at lowest price possible is to build it yourself.
Even then £1500 is very tight and will require you buying correct components from the right suppliers, most of who will be in China.
Then you need a good design and have the time, tools and skills to build it. Along with lots of research to fully understand what you're taking on and how the electronics etc impact the machine.

My advice (From helping many Chinese 6040 owners) is that if you don't want to undertake to build your own then don't buy one of these cheap machines and save up for the better machine. Either second hand or custom-built for you by someone like me or others on the forum. It will save you money and lots of frustration long term. (not to mention money in wasted Brass)