For me, the Snapmaker U1 is spectacular! A big upgrade from my previous printer (AnyCubic Vyper) in speed & quality and with multiple colours. Had mine for about a month now, and these are things which I particularly like (some of which I didn’t realise before buying):

• It’s open - no requirement for an account or to send prints through the cloud
• Track usage for any filament - using custom firmware (search “paxx12”), Spoolman, and cheap RFID tags (don’t bother with NFC ones) you can track all your spools
• Multiple nozzles is so much faster & less waste than an AMS
• Automatic switchover means I’m actually finishing rolls rather than expanding my bag of leftover filament
• Orca slicer just released a new version with colour mixing (alternating layers of colour to mix a different colour) - still trying to get used to it but seems super cool
• Built in print server - I love OctoPrint & it was incredibly useful for the Vyper; the U1 has a built in server (and is silent when not printing) so now it gets left on all the time instead of OctoPi

Some (minor) downsides:

• It doesn’t actually warn you if you don’t have enough filament left for a print
• Multicolour takes quite a lot longer to setup - paint the models, unload all the old colours, load all the new ones, etc.
• It’s a lot bigger than the Vyper (don’t know about the K1 size), especially since you need access to both sides for the spools
• Some spools have bigger centres (though of course there is an adapter you can print 😅)

I can’t compare it to the K1, but I can very confidently say that, for me, this is by far the best multicolour printer around this price point (would’ve liked to go Prusa with INDX but didn’t want to pay an extra grand 🙈)