4-spool dry box advice - Sunlu S4, SpacePi, or ???

Apologies if this belongs in the "buying advice megathread" but that seems to be intended for printers only, not other bits.

Anyway - I'm in the market for a box or two to put my filament in, get it dry, and then keep it dry without having to intervene as the printer lives in the shed so I don't go out there other than to collect finished prints.

I have a Prusa Core One + MMU3 so that means there's almost always 5 spools "out" and in use, and a box like the S4 would mean I can tidy the desk a bit as well.

Before we start: No I don't really want to make my own, I have enough projects.

I like the idea of a box that can run a drying cycle and then automatically maintain a level.

The S4 looks like it ticks the boxes, the SpacePi looks like a nicer design but isn't so clear on the "maintaining" part of the cycle and costs ~50% more.

Is there anything I should know, any alternatives I should consider, anything to avoid, any modifications I should look at?