Can they really make two different people feel that differently?
In one word, yes.
That shouldn't come as any surprise. You can pick any speaker on the face of the earth that has a respectable following and find those who simply don't understand what the fuss is about. A quick summary of the situation might be this:
1. No speaker is perfect. All have different strengths and weaknesses. This applies to the very expensive models, too.
2. Different people listen for different things. You might be impressed by dynamic range while someone else feels that comes off as too forward. Another person swoons over a speaker's ability to throw a razor sharp image yet his friend finds that razor sharp image unrealistic. Yet another person is struck by the incredibly smooth and neutral midrange while a fellow listener finds that smooth neutrality "dull" and leaden sounding. Examples like these could continue endlessly.
My take on Vandersteens is they are very good and I could happily live with them. They are a smooth speaker with lots of good points and no great flaws. That said, they've never quite had the magic for me they do for some others. I've got a pair of Spendors that do the trick for me right now.
However, you're going to have to be the judge on this subject. If you can get them at a good price and you know the pair in question is in good shape, it is a reasonable plan to just buy them for the sake of an audition. If you get a fair deal, they shouldn't be too hard to resell if they are not your cup of tea.