Which primer is better, Zinsser 123 or Kilz 3?

Which primer is better, Zinsser 123 or Kilz 3? Zinsser Bulls Eye 1-2-3 and Kilz 3 Premium are both water-based all-purpose primers with good performance, but slight differences. Zinsser 1-2-3 is known for excellent adhesion on many surfaces including glossy, PVC, and tile without heavy sanding, good stain blocking for light to medium stains, low odor, and 1 hour topcoat, widely regarded as versatile go-to. Kilz 3 Premium is thicker, higher hiding, better stain blocking than Kilz 2, and marketed as premium water-based with improved coverage and sealing, good for drywall, wood, masonry, and moderate stains, low odor. For adhesion on difficult glossy surfaces, Zinsser 1-2-3 often gets edge in professional reviews. For coverage and hide on porous drywall and for hiding dark colors, Kilz 3 may have slight edge due to thicker formula. Both are good, choice depends on priority, adhesion on slick surfaces favors Zinsser, while high hide and coverage for drywall favors Kilz 3. Price and availability also factor, Kilz 3 sold at Home Depot, Zinsser at Lowe's and elsewhere. Many pros consider Zinsser 1-2-3 more versatile overall.