I am not sure on the name of my girlfriends but it has the roll of toilet paper that the child spins and music when she tinkles and also sounds when the child "flushes". My daughter thought it was great... to play with!!!!!!!!!! She was way too distracted to even attempt to go potty and peed on herself and on the floor because she was too busy playing with everything on there rather than sitting.
We bought one that plays music when she tinkles but we have never connected the musical part (it also has the guard for little boys). Our daughter sits just fine on it and we praise her for it whether she goes or not. I do allow her to bring books in the bathroom with her or her baby etc but the potty chair is just that and nothing more! I will be the one to reward her and I do with lots of praise, clapping and high fives and even staring at her pee and poop telling her how great it is! lol To me the music makes it no more than a toy and then to try to transition to a regular toilet will make it more difficult-in my opinion!
I think no matter which one you choose, allowing him to observe will be a big thing and to just try it out for awhile. We had ours in our bathroom from the time she was about 15 months. She was partially potty trained for awhile until at 18 months I screamed at the dog for taking what she left in the potty and eating it like a Snickers bar! I traumatized her and she refused until recently to go on there again, although she would sit on it with her diaper on which was fine and praised her for that even. She is now at the stage where she tells me again when she has to go but it is a matter of making it in there in time. She also comes in with my husband and me- yes no privacy anymore- and praises us for going tinkle etc! It is really cute to see her high five us and then she will sit on hers and try her darndest to go as well- following our example.
So, basically what I am saying is... no chairs that are more toys than potty and praise is the best thing no matter what for learning! Also, no child will go until they are ready to! Be patient... it will not happen over night! I think it is wonderful though that you want to introduce him to it now.
Good luck and blessings to you and yours!