Anyone with knowledge on washing machines and dryers who can help me figure out what I should know to make a good purchase?

Firstly, are combined washing and drying a good idea or are there any significant downsides to it that I should be aware of?

What should I look for with regard to longevity and repairability?

What pricepoint should I aim for where you get good quality?

Brands to avoid or brands that tend to make good stuff?

boosts appreciated