I have Sword, and I'm enjoying it. That being said, it's far from my favourite mainstream Pokemon game (especially with the hand holding making an unwelcome return - that's what annoyed me with Sun/Moon).
I've seen times range from 10-40 hours for completion. I'd say it's more like 20-25 if you take your time and enjoy every aspect of the game. I've battled every trainer, caught some 'mons, gone camping, and given myself a personal challenge (never to evolve my Sobble, who's currently at level 61).
Also, reminder for those who don't go online with their Switch - you'll need to pay extra for a Nintendo Online account. Even if you play locally, you need to be face to face with them for things like Surprise Trade (this game's equivalent of Wonder Trade). I was at the Kingdom Hearts World of Tres Orchestra last night - there was about 5-6 other people playing. I set up a ST and I saw somebody else set one up which was when I realized - there's no actual way of accepting a ST with someone. It says 'searching', but nothing ever happens. That or both our games were glitched. All I got to do was enter a Dynamax battle with someone which apparently
is allowed. Either way, I was disappointed on that front. Wonder Trading kept me going for so long back in the day, even if most of the Pokemon I got from it were awful.
My team at the end (for anyone who cares): Sobble, Corviknight, Thievul, Arctozolt, Runegrigus and Meowth (the freebie one they give you via Mystery Trade - he never evolves, but by the time I knew it I was end game and couldn't find anyone I liked enough to replace him with).
I have Shield and while I haven't been able to got far (exploring more than following story line) I'm enjoying it. One of my friends is Meh about it and wishes they had gotten Luigi's Mansion 3 instead
To be fair, LM3 is incredible! Spent over 30 hours on it so far (and I don't have access to online modes).