On the contrary I recently saw the 50" Pioneer PRO-101 Signature next to the 500M. The 101 had superior blacks and the clarity of the latest Samsungs.
The KRP-500M and PRO-101FD are absolutely identical in terms of PQ.
If you saw a difference they either lied in the source, the settings, or both. Panel assembly, drive assembly, power supply, etc are identical between both.
If both are equally configured, there will be zero difference in black level, "clarity" or anything else.
There's the straight facts for you.
Others resorted to buying a different stand on Ebay
I've seen plenty of sealed, Pioneer factory stands for under $100 on Ebay.
Adding in the desirable firmware upgrade voids the Pioneer warranty.
You don't know this for certain (and neither do I). Also, the patch is available with an uninstall utility which reverts the display back to factory-stock *if* you fear that your warranty would be in question.
Everyone is stating they don't need a OTA tuner. Why not simple present the facts and let members decide for themselves?
This has never been a secret and is often stated when a monitor is recommended for consideration. These types of differences have also resided in a sticky thread on the top of the forum that has been there for months.
The cheapest prices are from unauthorized dealers
That's always been the case. KRP-500Ms have been available for under $1800 from authorized dealers, and the 600Ms for around $3000 from authorized dealers. In every case of a cracked panel I've seen here, the buyer was either refunded in full or they ended up with a problem-free replacement.