I am thinking of upgrading my current camera from the Canon T1i to the Mark II 5D. I've done some research on the Mark II and it looks great, solid, and definitely what I want. However, my question is this - Would it be worth the cost of the upgrade? Or should I just invest more money in lenses? I'm hoping to hear from someone who has owned both the T1i and the Mark II and can give me some good feedback on the two models. Thanks!