Cannot speak for actuall performance yet, not ran it fully on a major project - just smaller test projects testing reverbs and creating presets for them. And for that, just two tracks, just swapping reverbs it works just fine.
Plugin like Waves NLS or other console emulations, where on every track(or almost) - it's an excellent idea to use Mix recalls.
- should I use it at all, and which emulation and setting - even trying first or last in effect chain.
To do major swap all over a project - really cool.
As time goes one probably find a favorite to use all the time - but getting there and figuring that out Mix recall is invaluable help.
And even using it generating/exporting different mixes - as a batch job, unattended - will be interesting.
Just throw them in a player after export and swap and listen and compare - is one limiter doing a better job than the other.
But starting out on full project I will do a full Save Copy To first of project and work on that with Mix recalls.