If you do Big bang attack with H+S it goes in an downward angle instead of going straight!
And his Ex version of the Crusher knee Kick has invincible startup frames and it works as a DP so bring out your inner shoto and Dragon punch like crazy.
http://dbfgame.net/dbfz-tips-trick/ve... vegata combo tips and trick detail
As an assist character, the combo potential that Vegeta provides is unreal. If you use his assist, it locks your opponent in place and makes them incredibly easy to combo. If you can, use Vegeta only as an assist character, and rely on him as a back up character if all of your other characters are knocked out.
As an actual fighter, Vegeta is very underwhelming. His combo potential is mediocre at best. His Final Flash does very little damage in combo, but has really good vertical range. In my opinion, Big Bang Attack is a much better move, since mid combo it does around the same damage for less meter.