Graham, I have both of those PG and I advice you to choose the Strike, which for me is the best PG even if he is older than Exia.
Strike is better in term of articulation, build fun, design... Exia is cool about the LED integration but is frustrating in posing possibilities
because it has to be connected to the base to light up and there is (on mine) a problem in the hips which pops up everytime
your best website to compare each other (MG/PG and other) is: http://www.dalong.net/