My Grandson tried a 1997 MPI when he was 17. We bought the car for the right price, then did a comprehensive restoration. Lots of welding - wings, A-panels, front panel, door skins, sills, boot floor, rear valence, etc.
Engine was stripped, re-bored and carefully re-built. Brakes stripped and re-built, all new suspension bushes, replacement dampers, complete re-paint, new tyres, Mk.1 grille and lots of other odds & ends.
He drove it before and after he passed his test, then used it as an everyday car.
He spent a lot of time maintaining and servicing it until he got fed up with all the routine work. It was not unreliable as such, it was just a lot of work. Also it was not really comfortable.
In the end, after about 6 months he sold it for a good price and with 1/2 of what he got for it he bought a Fiesta 1.25 Zetec. This had power steering, leather, air-con, good audio system, needed little maintenance and was a great car until a guy in a big 4x4 wrote it off. With the insurance he bought my wife's old 2004 Mondeo Ghia Diesel which was a great car.
However, he can drive my Minis whenever he wishes, so he is still a Mini enthusiast.