I have both Spectraview II and Spectraview Profiler (which is available to people who own a BasICColor Display license... they are essentially the same).
Big differences are...
They are completely different applications developed by completely different teams. The only similarities they share are that 1) they wave the NEC flag and 2) they are calibration and profiling applications. Spectraview Profiler (as mentioned) is BasICColor Display. I don't know who wrote Spectraview II.
Matrix vs. LUT based profiles - SV II generates Matrix based profiles, SV Profiler can do LUT based profiles in addition to Matrix based profiles. Although LUT based profiles are technically more accurate, ultimately I don't feel that SV Profiler has any huge advantages over SVII in that specific regard.
Eye One Pro - I believe Spectraview II does a much better job with shadow details when using an Eye One Pro spectrophotometer. I noticed that SV II spends a little more time on the blacks so it has a longer integration time when taking measurements in the shadows with the Eye One Pro and as such I find the shadow detail to be more neutral with SVII. If you're using a colorimeter... there's no difference there.
Calibrating non-NEC monitors. SV Profiler will profile non-NEC monitors. SV II will only work with NEC Spectraview compatible monitors.
Validation - SV Profiler provides a little more information with regards to profile validation. Both display average an max dE but SVII doesn't really specify what it is reporting so if you see a measurement with high error... is it a color, is it greyscale? What? I don't know. While both show bar graphs with the error for each measured patch, SV Profiler's graph is (gasp) color coded (imagine that :lol: ) so it's pretty obvious as to what you're looking at.
Again, they are completely different applications so as an example it's kind of like asking "what's the difference between Color Eyes Display Pro and the Spyder3 Elite"? Fortunately, either one will do a great job. If you're using an Eye One Pro I'd lean towards SVII, otherwise they both work quite effectively.
Cheers, Joe