lol, neither side - commercial or fan - really respects the original material. Do you know what a translation team is thinking toward the end of the project - or even halfway through? It is very very simple... 'let's get this frigging over with so I can forget about this hell!' Quality is something you think about at the beginning and perhaps a few months after you finished the project, not something you are going to be thinking about at the end, unless you are insane.
One of the problems of trying to get a 'quality' translation out of anyone is that most companies and fantranslation groups are unwilling to seriously rethink the process itself when it isn't working. Fantranslators wait for a particular translator/editor/tlc to return, eventually causing the project to rot. Commercial translators are so focused on just getting it out of localization that they frequently make amateurish blunders that make fantranslators look better in comparison - yes, this happens surprisingly often.
Jast is an exception... but look at Jast. It takes them the better part of three to four years to get even the shortest of VNs released, and no one believes them for even a second when it comes to release dates. Any decent translator could have finished translating Hanachirasu inside a month if he was being paid to do nothing but that (that means using the time others use for their rl jobs for it), but instead it took five very long years. Do you have any idea how ridiculous an inflation of time that is?
Fantranslators have a much wider variance in quality, meaning that they can be so bad as to be incomprehensible or so wonderful they make the best commercial translations look like someone took a battle axe to the Mona Lisa. However, the majority of the curve tends toward the former, not the latter. Commercial translations tend to be more reliable in terms of quality... but that is a midline quality that never manages to do anything but 'get the job done'.
Simple things like a simple 'konbanwa' turning into 'Report, soldier' (actual example from Valkyria Chronicles PS3) are examples of wtf screwups by localization teams, but you see even more incomprehensible mistakes from some of the fantranslators out there (Kamidori is full of them, as an example played by many Fuwans).