My immediate reaction to both those is that they don't cost enough to be solidly built. But I don't have any practical experience, I have only seen them in a professional fitness centre (where I was not a user, I was doing english support teaching for one of the monitors).
On the other hand I have put the Dino on the turbo and yes, it is much more fun than being seated on a df on the turbo. You can watch tele, read a book, do the Times crossword, so much more easily.
Correction, I used one at the physio on re-education for my knee. That again appeared a lot more solid than the Amazon offerings (and it wasn't any more solid than it needed to be).
