You'll rarely hear anything good about being self-coached in the triathlon world, principally because there are so many coaches out there hawking their services. (This is not to say there aren't good or even great coaches out there, because there are. I know several.) People who have spent a lot of money on coaching rarely want to say that they wasted both their time and money doing something they could have done themselves, as well.
Frank Shorter (self-coached two-time Olympic marathoner) has a refreshing take on coaching himself that is well worth the click to read.