This kind of mirrors my experience, I was writing a gpg keyserver in PHP at the time when 5.2 was current and was using an extension[1] that wrapped gpgme. When 5.3 hit it stopped working and I had not enough time to fix it (I just saw it's gotten updates meanwhile) so I also moved to using the gpg binaries.

IIRC digging into the gpgme source and the ruby or python bindings didn't prove to be very reassuring though, but my memory might fail me there.

Good to know thought that gpgme is actively endorsed now, because at that point of time it didn't look like it.

[1]: http://pecl.php.net/package/gnupg