Its impossible to make sense of some people's preferences, and in a relationship its probably dangerous as well for personal items. The $600 version might be better made, or it might all be for the label. I can buy a pair of Men's shoes for $25 bucks and I'll be buying another $25 pair in 3 months if I wear them regularly. Or I could spend $125 on a much better pair, get them resoled for $35 every 6 months and keep them for years.

But in the end, none of that is important if those shoes are important to her. The only two legitimate questions are: "Does it fit the budget?" And "Is this some kind of crazy test that I will be repeating to prove she is still attractive enough every passing year?"

And really, who cares about the second question if the answer to the first question is yes? Its only when the first question is a no that trouble must be navigated.