PT2009 (606) Tested on x86 Vista BE pre-SP1 desktop
I didn't do a full registry snapshot and compare, just some shorter tests.
There are a few bugs. For example:
This bug is still in 1.9.0.590 and 1.9.0.606: http://www.macecraft.com/bugtracker/bug/112917/
An entry which did not change showed as changed in the list with corrupted data (this is repeatable, twice anyway).
"Change back" for that entry puts corrupted data in the registry entry (also repeatable). The backup is correct.
Some MRU items are listed even when "Ignore MRU entries" is selected.
Perhaps the crashes and uninterruptible loop or hang you are experiencing is due to another bug.
Since there likely will not be any further fixes to PT2009, someone can see what Registry Monitor does in the PT2010 betas ...