I'm sure you know the basics but just in case, the X rating is the amount of beaver fur (relative to other furs like rabbit) that is in the felt used to make the hat. 20x is a very high quality hat, lots of beaver, hence the high cost. The Black Gold hats seem to have a bit softer hand than the standard 20x. It's a tad more 'furry', and I mean a tad, not like some hats that look like a pelt in the shape of a hat. It gives the felt a really rich dark look.
I've had one of these for about 7 years and I wear it a lot. It's not a hat that I've saved for dress occasions at all. It has held up very well. I take good care of it but it's been in rain and snow, been reshaped several times, and every time I brush it up it still looks great. I recommend it highly.