So assuming your i1Pro has been looked after and is still passing certification, is there any reason to upgrade to the new model?
It appears that the biggest changes here are:
1) Better temperature stabilitya non-issue if you allow time for the meter to acclimate to the room before starting calibration, and use it as a non-contact meter. (I never use it on a display now)
2) Better low-light handling due to adaptive integration time... something that has been implemented in CalMAN since v3?
3) Better stability so that the meter no longer needs frequent dark offset measurements. If you are using the meter in a non-contact fashion, this takes all of two seconds to either hold the baseplate up to the meter and press the button on the meter to take a dark reading (at least that's how I have it configured in CalMAN) or even easier if you have the beamer attachment, where you just flick the window closed.
It seems like the biggest change here is for print work with the integration of a UV LED, rather than there being much for display calibration. (though I suppose it will fare better in other display profiling packages that take more than 10 minutes to complete, and don't take new dark offset readings)
Actually, now that I think of it, has the i1 Beamer been discontinued as well now? Perhaps I should finally get a hold of one. I've been meaning to for a long time, but kept putting it off due to the price. (seems rather bulky too, but nothing else has a window for the dark offset readings)