Ok, this is going to be like my 10th time repeating this, but...
I have directly compared the HP1000, GS1000, PS-1, RS-1, RS-2 and L3000 (and several others) side by side.
The HP1000, was by far and away, the best headphone out of all of them. Period. The closest competitors were the L3000, GS1000 and PS-1. But, I preferred the HP1000 to any of them beyond any shadow of a doubt -- there was no gray area where I said "well the HP1000 sounds great but so does the L3000, I can't decide between them...", etc...
But, probably the biggest surprise was how poorly the RS-1 and RS-2 compared to the HP1000. There was simply no contest, the differences were HUGE. It made both the RS-1 and RS-2 sound like some kind of fisher price toy headphones. Literally. I am not exaggerating. It was to the point that I would have been hard pressed to find any positive words for the RS-1 and RS-2 in comparison. The difference really was THAT big.
And no, I am not at all interested in the HP1000 for collectors value. I bought it for the sound and the sound alone. If I wanted it for collectors value I would not have purchased the APureSound restored HP-2 (see sig for pictures). There were 2 or 3 other pristine HP-2s that were also available for me to buy which would have been much better for resale and collectors value. I passed.