Yes they are. If opensource product A does not have better features than competing opensource product B, uses move to the better product A and pretty soon, almost nobody will use product B. Take BSD vs Linux for example. We get "we've migrated to BSD" or "we've migrated to Linux" posts all the time and arguments for one or the other. Is there a winner and loser? Yes. Larger communities, more developers, more corporate sponsors, more contributions, etc. Certainly looks like competition to me.