I feel like as an old man I just need to start doing write-ups on these types of things because no school teaches you anything close to this anymore.
Front-load: Better cleaning efficiency, gentler on fabrics, uses less water and energy. Downsides: door seals can mildew, must bend to load/unload, generally pricier.
Top-load (impeller): Faster cycles, easier loading, cheaper upfront. Uses more water, may be harsher on clothes.
Top-load (agitator): Good at removing stains, but tougher on fabrics and water-intensive. Mostly phased out in newer models.
Recommendation: If you can find a top-load with agitator within your price range that will fit where you plant to place it: go for it. Front-load looks better, but unless you're running it all of the time it will mildew and the cost is usually not worth that.
Capacity: Look past the cubic ft (or kilograms if you're not in the US), consider how often you do the laundry, how many people will be doing the laundry, and what you expect to be washing.
Recommendation: Aim for 4.0-4.5cu/ft (14-15.75kg), that's a nice happy medium that can do both light and heavy loads without much issue.
Steam cleaning (sanitizes, reduces allergens)
Quick wash (for lightly soiled items)
Sanitize/high-temp options (good for baby clothes or gym gear)
Automatic soil sensors adjust water/time
Recommendation: Avoid gimmicks you won't touch—extra screens or specialty modes add cost without benefit if unused. Your washing machine doesn't need wifi, bluetooth, or voice commands. It's just more stuff to break.
This section is a little harder, personally I go with Bosch, Speed Queen, or GE Profile; but depending on where you are and your budget you might not be able to afford them. That being said, an ex of mine worked for an appliance warranty company that serviced multiple brands and they always said one thing: We're never getting a Samsung or LG, they have more warranty repairs than any other brand even accounting for their popularity.
I hope this helps someone who's looking for their first washing machine.