Hi Branman
You can find a lot of info on both these bikes on my website as I have owned a customised Birdy Red and currently own a GoBike X9 :-
http://www.long-john.com/pagegobike.htm
http://www.long-john.com/pagebirdy.htm
Both bikes are great, but both have their downsides, one day someone, somewhere will get it just right...............sort of!