Almost every serious mousepad decision comes down to this one. Both surfaces can be excellent. They fail in different ways, and knowing which failure mode you can live with is the actual decision.
Glide
Cloth: ranges from very slow control weaves to genuinely fast hybrids. Glide comes from the weave, so it changes as the pad breaks in and again as it wears.
Glass: smooth and low-effort across the whole range, with the character set by the etch rather than by a weave. It does not break in, so what you feel on day one is what you get.
Stopping power
Cloth wins on absolute stop. A dense control cloth will park a mouse harder than any glass surface. If you play at very high sensitivity and want the crosshair to feel nailed down, cloth still has an edge.
Glass wins on predictable stop. The stop is lighter but identical every time, which for many players produces better results than a stronger stop that shifts with humidity and wear.
Consistency
This is not close. Cloth absorbs sweat, responds to room humidity, breaks in over weeks and wears out over months. Glass does none of that. If you are the kind of player who notices that your aim is different on a humid evening, that difference is real, and glass removes it.
Lifespan and cost
Cloth: lower up front, six to eighteen months of competitive life depending on how much you play and sweat.
Glass: higher up front, effectively unlimited surface life. The consumable moves to the skates, which wear faster on glass and need replacing more often. Over three years the totals land closer together than the sticker prices suggest.
Noise
Cloth is near-silent. Glass makes a distinct sound. If you stream, share a room, or simply dislike the noise, that is a legitimate reason to stay on cloth, and no amount of performance argument changes it.
Comfort
Cloth is softer under the forearm. Glass is cool and hard, which some players prefer and others find abrasive over long sessions. An arm sleeve largely neutralises this and also stops sweat from reaching either surface.
Sensor tracking
Both work with modern sensors. Uncoated etched glass tracks extremely cleanly. Very dark, very glossy or mirror-finish surfaces can cause problems, which is why a proper glasspad is etched rather than polished.
Portability
Cloth rolls up and travels in a tube. Glass is a rigid panel that has to be carried flat and protected at the corners. For LAN players this matters.
So who should buy which?
Choose glass if you practice deliberately, play long sessions, sweat, or are tired of your surface being a variable. Start with the glasspad range.
Choose cloth if you play at high sensitivity and want maximum stopping power, you need silence, you travel with your pad, or you simply prefer a soft surface. The cloth range is built around a Poron base so it stays consistent far longer than a typical rubber-based pad.
Whichever you pick, fix the skates
More people are unhappy with their pad than should be, and the cause is usually worn PTFE. Fresh mouse skates change the feel of any surface more than switching brands of pad does.