Currently own: GC, GBA, DS, 3DS, Switch, PS5.
Owned in the past but no longer own: PS2, PS3, WiiU.

Gamecube is the least selling system I still own and it is worth it by a far margin. Still sees regular play when my siblings visit.
Even the WiiU that I no longer own was worth it just to play Mario Maker.
3DS that I still own, I think was not worth it for me. Played mor regular DS games on the thing than 3DS. Only kept it to play the Ace Attorney games that I bought for it. But now that I have all of them on the Switch, I might get rid of it.

The OUYA.

And was it worth it?

Not having had much, it'll be Master System. And hell yeah, I'm still playing it at least once a year - tradition to dig it out for christmas. Though it's just barely running: image blurs, one pad left barely taking all buttons (and D-pad is broken), takes few starts to get it to read cart and light gun won't take from side of screen...
But with 36 years coming up and with some rough treatment at that, certainly worth it. It'll be a terrible day when it no longer turns on.

Get a cap kit from console5 and send it into a reputable modder to get it recapped. Buy a  new PSU from FirebrandX's PSU website. It will be a triad PSU. Then get a new controller from Retrogameboyz. They custom build new controllers for SMS with new pcbs and their controllers just feel right. They are out of Europe. It should run like new for another 40 years. Also there's several mods from Zaxour that improve the image output on a CRT. 

I'm looking forward to the new AES.

Enjoy! It's an awesome system, albeit rather niche.

Game Gear, Saturn, Dreamcast, Vita, Wii U. Yeah, Had fun with all of them. But I wouldn't have gotten any of them if they didn't have notable libraries.

I also had a Game.com. That was absolute dog shit. All they had to do was copy Game Boy with a little more power. They didn't do that.

Absolutely not!  :)