Hi Graeme, it seems that i1pro 2 seems to overal a facelift blows-and-whistles trendy WORSE unit overal compared to i1pro?
Overall I think it is an improvement with regard to measurement, with the wavelength calibration, UV illumination capability, zebra ruler sensor and temperature drift tracking cells.
In other ways a slight step backwards, the power supply sensitivity being one, and (maybe) the incandescent globe being more subject to tungsten accumulation and resulting thermal drift effects that earlier models.
They claim 300 or 400 cd/m2 ceiling measured luminosity although I have put mine to direct sun reflected on ceramic building walls recording if I recall correctly over 30000 cd/m2 with no damage and stable dark measurements after that. Not that I would recommend it but still...
I got the impression from my testing that full sunlight ambient readings were about the limit for the i1Pro. That's not bad though - the ColorMunki spectro is much more limited, due to it not allowing small integration times.