In the first model the friction of the strings was achieved by a mechanical bow traveling sideways. The second model featured a single rotating wheel, similar to that of the earlier hurdy-gurdy, to play strings. It differs in that a hurdy-gurdy has a small number of strings that are constantly in contact with the wheel, rather than a larger number of strings that can be lowered onto the wheel. A hurdy-gurdy has a keybox with tangents that change the pitches of the strings, rather like placing fingers on violin strings. Leonardo's innovation of a keyboard with a lowering mechanism allowed individual notes to be played, alone or in specific desired chords over a large range of pitches.

https://en.wikipedia.org/wiki/Viola_organista#Description

In terms of sound, the instrument in the video in the posted article is not at all like a hurdy-gurdy. I find it sounds like a string quarted. Perhaps it's more the kind of pieces that are normally played on a hurdy-gurdy that tend to have a very folk-y sound, whereas the gentleman in the video above is playing a classical piece. But I don't think I'd really mistake this for a hurdy-gurdy.

All of which reminds me- man, I'd love to learn to play the hurdy gurdy. Damn expensive instrument though.