I have the Scallywags On Board Rolling Board attached to my Mamas and Papas Ultima pushchair with mpx chassis.
It's a lot cheaper than some brands so I was a bit of a sceptic - assuming it would be flimsy or that it wouldn't fit to the pushchair. I was wrong!
The board is sturdy and attaches and detaches easily, I was surprised by how light it is. The clips which attach it to the pushchair fix on and off easily too so it isn't difficult to swap it onto a different buggy. I thought I might hit my legs on it as I walk but I never do (I'm 5'6") and it clips up well out of the way when it isn't being used. I was also concerned that it would be a struggle to get up and down kerbs but I manage both o.k. - with care!
I do have a couple of gripes; firstly, I had to attach it to the inner poles on the back of the pushchair which aren't as strong as the outer legs because the board wasn't wide enough for that (the poles are, luckily, strong enough). Secondly, the way the clip which holds the board up when you aren't using it attaches through a hole in the buggy board is a bit awkward but I've put a split ring through the hole and it's a lot easier to clip up now.
My 3 year old loves riding on it so we don't have so many problems with him running off at the shops and if he's really tired he sits on the board with his feet in the shopping basket!
I think this board is great value for money and I'm so glad I bought it. I kept hold of our double buggy "just in case" but I'm glad to say we haven't used it since we got this board.