Transition from 12C to 650s - Worth it?

[Pluggy101]

I currently have a 62 plate 12c and looking at possibly replacing it. If I was to stay with Mclaren the obvious progression is to buy a 650s. Before I look to test drive one can any previous 12c owners who have made the move to the 650s provide their insight/views - worth the additional financial outlay? Iris work? Vehicle lifter give adequate clearance over mild speed bumps? Is the performance increase noticeable? Thoughts on 650s values going forward? Anythig that is a must on the option list if I go new, or spec I should hold out for if I go used? I also welcome the views of current 12c owners who can advise why I should keep the 12c :-)

Many Thanks in advance.