What is better, Zinsser or Kilz?

What is better, Zinsser or Kilz? Whether Zinsser or Kilz is better depends on specific job, budget, and preference, both are reputable primer brands. For general all-purpose water-based priming, many professionals rate Zinsser Bulls Eye 1-2-3 slightly better than Kilz 2 for adhesion on glossy surfaces and light stain blocking, with low odor and easy cleanup. For heavy-duty stain and odor blocking, Zinsser B-I-N shellac-based primer is generally considered better than any Kilz product, as shellac seals smoke, fire, pet urine, and nicotine most completely. For oil-based heavy stains, Zinsser Cover Stain and Kilz Original are comparable, both strong, with personal preference. Kilz Original oil-based is good budget option for heavy stains, while Kilz 2 is cheaper than Zinsser 1-2-3 for basic drywall. So Zinsser often wins for specialty problem surfaces and adhesion, while Kilz offers good value for everyday and heavy oil-based. If you need best performance for worst stains, Zinsser B-I-N is usually considered better. For general DIY, both work, but many pros keep Zinsser as go-to for reliability, though Kilz is widely available at Home Depot and cheaper.