I can only give you my own experience.
A computer I bought from them many years ago is still working perfectly but I would not buy from them again because of the way they tried to sell me their insurance. It was so bad that I was on the point of telling them to keep their computer and leave the store.
Perhaps things have improved since then but my experience has made me very unlikely to consider purchasing another computer from them.
You should be covered by the sale of goods act if there is anything wrong with the computer.
The bundles they sell appear to be good value but you can usually find the same or better elsewhere if you really search around.