From a management standpoint alone, R81/R81.10 is worth the upgrade as the speed improvements are really noticeable. Also, bonuses which are appreciated by the customers like NAT hit count, Web Smart Console, updateable Smart Console and concurrent policy installation.
Now on VSX, I have to say that R81 and R81.10 are really stable. With R80.40, I had recurrent routed issues requiring private hotfixes or tweaking which went away after upgrade.
Accelerated policy installation is also a nice to have on the long run in the times when a policy is fine-tuned, requiring multiple policy installations in a row.
My first R81 upgrade went bad but it turned out to be a series of external dependencies, but top job from Check Point for this new generation of Gaia OS.