AIR COOLER PROS: Air coolers are more reliable by virtue of simplicity. Even a liquid cooler with a 6 year warranty is going to have very slow evaporation, and are prone to slow deaths from manufacturing errors that are not immediately apparent. Liquid coolers also have many points of failure, from the pump to the hose attachments to the fluid itself gunking up. An air cooler effectively has one point of failure: the fan dying. This is both extremely rare (my computers from the '80s and '90s have their original fans) and very easy to fix by just putting on a new fan. Air cooling is also less expensive at most cooling tiers than liquid cooling due to both less material needed and less complex manufacturing, with best-in-class air coolers available for US$65 (or less on sale) and entry-level air coolers starting at around the cost of Taco Bell lunch for two. LIQUID COOLER PROS: They have higher maximum cooling capacity from being able to dissipate heat over a larger surface area. The larger thermal mass means they can absorb sudden bursty loads more easily and take longer to saturate (though this also means they take longer to cool down once heated.) They have benefits for aesthetics and space fitting - a large air cooler can make it difficult to interact with the top PCI-E slot for example, and some small cases cannot fit large tower coolers at all, necessitating water cooling. Personally, all my (too many) computers are air cooled, because I like slapping a cooler in there and then just not having to think or worry about it anymore, and even my 11900K is comfortably cooled by an inexpensive AK620 cooler. I see the virtues of water cooling, but feel that they are used too often in situations where they are either completely unnecessary or provide little benefit over an air cooler, though there are plenty of situations where they do make sense. EDIT: To clarify, I am referring to closed-loop coolers, or CLCs (also known as AIOs.) Custom loops are outside the realm of the casual builder and one needs to go into custom loops with a lot more knowledge and forethought than just buying an H115i and bolting it to the top of your case. EDIT: I've edited this comment like four times now to add more info, it was originally a concise answer to one person's question but it's turning into a got dang treatise Answer from VoraciousGorak on reddit.com