Not sure about VDJ8, VDJ7 wasn’t really good at 65% accuracy (according to the 2014 comparison done by our friends at DJ Tech Tools).
Actually Keyfinder did do slightly better at 77%. This still means that a whopping 1 out of 4 is wrong. So if you have a core collection of 2000 tracks, you have 500 tracks not properly keyed. If you are serious about harmonic mixes, this is a huge bottleneck, imho.
Now I don’t recall paying for the latest MIK upgrades or ever (but I might just have forgotten) and the price might seem high. But frankly, at 95% accuracy, it’s the best thing out there, even if you don’t use any of the extra features like the energy rating. I am a big fan of the camelot notation (not a musician myself), so that being native to MIK is a bonus for me.
In the grand scheme of things, the software costs less than a good needle did in the old vinyl days and I went through 2 a month of those, so in comparison this is a relatively low investment. Together with Platinum Notes, these two programs are a the core of my music processing workflow before stuff hits my DJ software.
Just my two cents, as usual