Does each faction have a defining playstyle or are tactics based on the individual ships that are purchased? For example I like my armies to have movement tricks and lots of manouverability on the board is a particular faction stronger then the other at this?
Imperials have access to the two single most maneuverable ships in the game - the TIE Phantom and TIE Interceptor. The Rebel A-Wing comes close to the Interceptor (the A-Wing has slightly better movement dial but no Barrel Roll) but nothing matches a Phantom. Imperials also get the TIE Defender, which has limited turns, but is the only ship in the game that can perform a 180 degree flip without negative consequences.
Each faction has ships that are capable of filling all the various roles, but *generally* you'd probably get on better with Imperials than Rebels if movement tricks are your thing. However it's perfectly viable to run a tricksey Rebel list with A-Wings and the Outrider.