I'm on Optimax 3.1 and CTcaer 2.8 for months. Nothing wrong with it. Still as fast as it was when I installed it.
Things need to taken care of:
Cache, it eat /data partition space, leading to crash, FC, unexpected behavior --> Link2SD to get more /data space, clean up unused app, delete cache of heavy app montly (or when you bored) by sorting them by cache size in Link2SD and use Stock App Manage to free them.
Mem Gapps get heavier day by day, and other app by big corp. too. Especially Google+, so much resource hungry, always stay in memory. But if you left it out, many things will not work. Greenify is what you need, only service, keyboard and whatsapp allowed to run in background all the time --> save so much resource, always have mem when you open another app.
SDmaid and media scanner is something needed to run sometime, I'm not so sure about how it affect the performance, but having more space and less trash, better map of SD card is always good.
And last thing is, don't saving too much battery, keep min freq. at 245Mhz, max freq. at 1.2Ghz with smartassV2 and sio. Min freq. lower than 200Mhz screw up the phone the moment you press the power button to wake it up when it in the middle of running something in wakelock, like syncing or cron jobs. Simply not enough processing power.
ST18i and other boring Androids...