The reasons I decided not to use it for anything serious:
- very small community, dominated by a few guys in total and consisting of a strange mixture of old aviation/military/embedded industry professionals and a bunch of clueless beginners; there is just not enough of a community.
- almost complete vendor lock-in, AdaCore makes the only usable modern compiler and the FSF version based on it is always way behind
- no optional gc - memory pools are not convenient enough for my needs (as some Ada fanatics will emphasize, nothing in the specs prohibit a gc, it’s just that no Ada implementation comes with one…)
- strange licensing conditions and future uncertainty about licensing: AdaCore’s version requires you to publish the source code of your program under GPL, FSF version with mGPL allows you to develop proprietary software, but many essential libraries are not mGPL
- Ada’s plus is one of its perceived disadvantages: Many libraries are old and unmaintained. The reason is that Ada is so good, once the library runs it does not need to be “maintained”. But it still feels bad to use something from 2005…
For 4. all libraries are now with linking exception.