Definitely prefer the ones with mechanical parts rather than the modern ones with eyes that are just backlit screens. I've always found animatronics fascinating, and it's neat that they managed to sell what was effectively a mini animatronic at consumer prices.
I'm a big fan of the various mods of them that people make, like the long furbys, hydras, etc. I'm sad that most of the mods don't go farther, like custom microcontrollers and such. I'm shocked there isn't some open source project to replace the guts with an rPi Zero or something hackable.
I personally think Shelbies are the superior Furby race. You can tell, since there is only one generation of Shelbies - there was no need to reboot or remake them, as they were designed to be truly perfect. I think Shelbies are the closest thing to what God may look like. Also their protective shells make them ideal warriors.
Long Furbys are cool too. You raise a good point though. Computer-people have busied themselves too much with open alternatives to corpo laptops and processors and architectures and some other stuff. Maybe it's time for an OpenFurbi (we'll have to change the spelling because trademark). You should make a kickstarter.
I'm still creeped out by Furbies and even Teddy Ruxpins. A machine that looks like it's alive, repeats nonsense or repetitive questions, is a Terminator or Screamer, just doesn't have the final firmware installed yet.
Thou shalt not make a machine in the image of a fuzzy object that talks.