I'm also using a S4 but do not have this problem. As TTS, I can recommend "SVOX", but it costs a few bucks.
Regarding crashes, - could you upload the crash reports to Google Play so we can check this? If you have your device in debugging mode, you could also capture the logs with "adb logcat" or "adb logcat >log.txt".
I have migrated from galaxy note 2 to galaxy s4. Now I face problem with rungps. TTS crashes my phone (IVONA), samsung tts is not working or working sometimes.
Another strange crash I face when I want turn on screen again - sometimes it crashes run gps. When I turn on my phone again all text is invisible - check link provided. I have android 4.3.2 and load own map tiles. Is it memory problem?