So I’ve been living with the cup holder I fixed onto my Bugaboo Frog, and I’m happy to report it works pretty well. I road tested it at the mall, in the airport and on the street where it held my drink (usually a bottle) within arms-reach and without spilling. I was also able to get it on and off of the stroller pretty quickly and stow it away in the bag underneath - even during the pressure cooker of airport security. The cup holder itself doesn’t feel that sturdy, but this is a function of the crappy Prince Lionheart cup holder and not the way I attached it to the stroller.
I did come across one issue though. Usually when I’m out with the stroller for a while I’ll hang the diaper bag over the handlebar of the stroller (using the Bugaboo bag clips). The problem is the drink in the cup holder gets in the way of the strap. This might not happen to your diaper bag (the strap on mine is rather wide) but it’s something to look out for.
In the end I guess I'd give it a B minus. It would be better with a cup holder that was more sturdy, a little better looking, and didn't interfere with the diaper bag. I’m still going to look for other attachable cup holder type devices to see if I can come up with something better, but for now this is working.
Previous: Bugaboo cup holder. Round one.