From someone who was at AE then another major and now Comair....lateral move is dangerous. If you enjoy where you're at, stay put. I believe someone mentioned on here that an 18 month upgrade today can turn into 5 years tomm. That is VERY VERY accurate. On the flipside, a 7 year wait may turn into an 18 month upgrade. Get the exp. not so much in flying but in ops and regulatory exp. so you will be ready for that upgrade, when it comes. When your time comes for the upgrade, flying the airplane is notthe issue but rather your enviromental exp, decision making and leadership skills. \
Good luck in whatever decision you make.