I have a 2012 614ce, a keeper. Very happy with it.
I found a used 2008 614ce, priced right. I'm in a 30-day evaluation, return permitted, of the 2008. I replaced its strings with fresh factory standard Elixir 80/20 nano lights. I tightened the truss rod nut a bit to reduce an excessive amount of relief.
Between the new 2012 and used 2008 models, here are the differences I'm experiencing:
1) The 2008 model is harder to play. After a while it hurts my fingers to play it. The 2012 model plays with less effort, and no finger pain.
2) The 2008 model feels heavier than the 2012. Both have a battery installed. One difference could be less/different ES hardware with the 2012 vs. 2008. It seems to me the 2008 woodset is heavier than the 2012 woodset.
3) The 2012 seems more alive/resonant. I can more readily feel the bass notes through the body of the 2012 compared to the 2008.
The biggest issue, and it is a show-stopper, is (#1 above) the 2008 just hurts to play after a while. The 2008 looks to be set up like the 2012, same neck relief, same strings.
Have you ever had this happen? I am pretty surprised by this, and will probably be returning the 2008.
614ce, 2008 (left), 2012 (right):

2008 614ce Fretboard at Nut:

2008:

2012:
