merchant banking / prop investing-> megafund PE?

Hey guys,

I'm considering a couple of options now. a generic bb group and a prop investing position of a second tier international bank (think deutsche/RBS/UBS). The prop investing position is basically the merchant banking principal investing arm and invests 50-500mm equity in various industries. from what friends have told me banking is the safer choice but i will end up spending a lot of time doing stuff like formatting and presentation whereas for the investing position it seems a lot less bs work. i expect to be exposed to lbo modeling at both places.

if i join a principal investing desk it is then possible to lateral after 2-3 years to a megafund p/e shop? if not BX/tpg/carlyle then second tier like hellman/dearborn?

thanks!