Well I've had it for a full day and I can honestly say based on what people are saying this is my own opinion.
I much prefer to play in Docked mode. Yeah it is a little fuzzy and the Depth Of Field effect is a bit OTT imo but aside from that it looks great. I've not ran into any problems at all and honestly it's just refreshing to have a game as good as this run as good as it does on the switch. It really is a Technical Marvel.
Now I actually like playing in Handheld mode for doom aswell. I actually thought I was gonna hate it cause I can't play Splatoon 2 in Handheld and usually I use motion controls for that but it does work surprisingly well this way. The only thing that really is Jarring is how much worse the game looks in this mode, to me at least, especially since docked and undocked basically have the same resolution for the majority of the time.
It's a great game though. I've run into the audio bug once where the sound completely cuts outand that really the only bad thing I can say about it.
If any team were to deliver their game like what Panic Button have done. Regarding AAA games that are too much to tun on the switch then I'd be happy.