Agree. Like I said, I don't espouse the notion that a critic should need to buy a disc just for comparison.
I maintain a Netflix mail membership partly so I can do comparisons with discs I never reviewed in the first place, but that's the end of my monetary investment! :D
Though in the...
I try my best to offer comparisons between different versions, as that's part of the job.
If you own a prior release, you need to know whether the new one is an upgrade.
I don't claim all reviewers need to perform heroic measures to do this - I don't argue the Todd needed to buy the Criterion...