Buyers should prioritize filtration systems, specifically multi-stage filters (activated carbon, ion exchange resin, and high-density cotton) to ensure water purity. The pump technology is critical; look for ultra-quiet brushless pumps with a noise level below 30dB and dry-burn protection to prevent motor failure when water levels are low. Additionally, the material safety must be verified, favoring 304 food-grade stainless steel or BPA-free ABS plastics to prevent 'feline acne' and ensure long-term durability.