I am a hesitant to fit different PSUs into equipment I paid a lot of money for, I like to think Meridian did a lot of research into which PSU to fit in the design stage.
The new linear PSU may very well be an improvement but equally may not! Why not have the Meridian health check and get a new PSU fitted and 5 year guarantee, just a thought?
You might be surprised. The electronics marketplace is flooded with triple-output power supplies offering exactly the voltages and currents required for Meridian equipment. They all have much the same specs, and the ones used by Meridian are very generic and much like all the rest. They don't have any better line or load regulation, noise, ripple, leakage etc. than any other off-the-shelf supplies. The chosen supplies attributes are size, weight, efficiency and cost. In other words, all the things that shouldn't matter much with big, heavy, expensive high-end audio controllers and players.
Having said that, I'm sure that Meridian DID design the capacitor board on the 800-series very carefully indeed. But it wasn't enough; not nearly enough.
Nick