Favorite:

• Nintendo DSi - The DS just had such an incredible library, with tons of unique titles you could never experience elsewhere. Though the sad thing about how unique it was is that… you can’t properly experience a lot of these titles elsewhere. Emulation just isn’t the same. While it came out very late and wasn’t worth upgrading to if you already owned an earlier model, the DSi was a very nice and sleek evolution on the hardware. Much more softmod-friendly too.
• Miyoo Mini Plus - Bought this last year on sale as an impulse buy. Ended up liking it so much I wish I’d bought a more expensive model with analog sticks. My ultimate dream is to someday get something that runs SteamOS in this form factor.
• My custom built fightstick - Put this together last year to replace my old Hori RAP4. Really happy with how it turned out! Love the GP2040-CE, I used to have to go through an adapter to use the HRAP4 on Switch and I can feel the difference not having that added latency anymore.

Hard for me to name least favorites, because I haven’t owned a system I actively disliked, and I don’t wanna just say CD-i or N-Gage or whatever. But I guess I’ll list ones that I have mixed feelings on:

• Wii - The Wii had a few great games. It also had a lot of duds. The saddest thing about it is how many games had to shoehorn waggle gimmicks in, and how few of them actually did it well.
• Steam Deck - As a Linux nerd that wants to see the platform grow, I love that the Steam Deck exists. It’s arguably the most important thing that has happened to Linux gaming. It just isn’t for me at all. It’s too big to be a handheld, I grew up on a Game Boy Color and I still love curling up with handhelds in bed, but this doesn’t feel cozy to play with at all. I do occasionally use it + dock as a portable setup I can take to FGC events, or when I have guests I’ll sometimes hook it up to the TV for Jackbox, but it mostly gathers dust the rest of the time.
• Switch - Great library, and the hybrid form clearly worked out for Nintendo just because they don’t have to divide their output between two platforms. But like the Deck, it’s not what I want in a handheld, mine doesn’t leave the dock. It’s also rather frustrating how many bad ports the system got, I wish developers would simply stop trying to port games it clearly can’t handle - especially when there are plenty of older titles in their back catalog that I’m sure could have good ports but get overlooked. And don’t get me started on JoyCons!