What a countertop rack is for
The bottles in rotation. The four or six you opened this week or will open this month, kept somewhere sensible and visible instead of lying on a worktop or standing in a cupboard door.
That is a genuinely useful job, and it is a different job from storing a collection. Judge a countertop rack on footprint, stability and whether it gets in your way — not on capacity.
Fold away or stack up
Two opposite philosophies, and which one is right depends on whether your constraint is space or growth.
The Mini Wine Matrix is four bottles in matte black metal, and it collapses flat. Nothing else here does that. Four bottles is the right number for a dinner table, and when the dinner is over the rack goes in a drawer. If your counter is contested territory, that is the deciding feature.
The Halfpipe is the opposite bet: two 3-bottle matte black iron units that stack, with no assembly at all. Start with six bottles; add units later and the rack grows rather than being replaced. Iron construction at a countertop price is a better material than the coated wire this price bracket usually buys.
The honest caveat on stacking: a stacked rack is only as stable as the surface under it and the care with which it is stacked. On a solid counter, fine. On a wobbling shelf, not.
Why this is not storage
A countertop rack puts bottles in the warmest, brightest part of the house. Kitchen counters sit near ovens, hobs and windows, and kitchens swing several degrees through a day of cooking. For a bottle you will open this week, that is irrelevant. For a bottle you are keeping six months, it is the worst spot in the building.
So use these for rotation and put the keeping bottles somewhere cool and dark — a floor rack in a cooler room, or a cabinet if the room cannot be trusted. The comparison is in rack vs fridge, and what temperature swings actually do is covered in wine storage temperature.