I've only ever had washer driers, they are great for me but I only use the drier for finishing off when I can't wait. The smaller wash load capacity would be limiting for a big family too. I can recommend Ariston but that's my personal experience.
trouble is with a washer/dryer you ave to wait for the dryer to finish( if you cant dry it anywhere else) before you can put another load of washing in
I don't believe a combo can be as good as two items each designed for a single function. And when one goes wrong the lot needs sorting. I think if you have the space go for separates, if you are tight for space, then the combo may be a solution.
Washer driers are fine for a couple especially if you only need the drier functon occasionally. If you are a family with limited outside drying space then go for separates.
I've never had large kitchen nor anywhere else where I could use a dryer so I have always used washer/dryers, my first was a nightmare but I eventually got a Bosch washer dryer which finally died after 11 years of use, I'm now on my second Bosch and it's going well. Unless I had a house with a separate utility room I'd always go for a washer dryer.