As both a software developer and an 18-year+ contributor to Wikimedia projects like Wikipedia/WikiBooks/WikiVoyage, I've written a lot of markdown...a LOT. It gets the job done, no doubt, but the only thing it has going for it is the first-to-market advantage. The specification (Commonmark) is ridiculous...
ProSupports semantic markup
ProShorter, more concise than Markdown
ProSupported by GitHub
Mainly aimed at web developers, this web app can carry out all manner of "cyber" operations in a web browser. Change character encoding, regular expressions, compression, encode XOR or Base64, more complex encryption like AES, DES and Blowfish, creating binary and hexdumps and much more.