I've had a W/D all my married life (not the same one!) and I wouldn't have been without one.
They absolutely do do both jobs well - the only place they fall down is if you want to do a wash/dry cycle with a full wash load, as they don't dry as many clothes in one load as a designated drier.
As you can't do that with separates, it's not really comparing like with like to complain that a W/D is not so good at that. I love being able to put a load in, go about my day and come back to a dry load of washing, rather than have a wet load that I have to dry at the end of the day. This was such a boon when I was out at work all day, but less of an asset now that we are stuck indoors, of course .
I have always had Bosch or Seimens models, and they have all lasted for years, including the one that saw me through two children from birth to about 15.
If you have space for it, and enough washing to make it necessary, a W/D and a separate drier would give you the best of both worlds, as you could be drying one load whilst washing the next.
I got my first one as a wedding present, and chose it because the kitchen in our first house was small, so it saved space. We have had three houses since then, all of which could easily have taken separates, but I stuck with the W/D arrangement, as they are so convenient.