I have owned the TOP version, and although I never used it in its stock form I could tell it sucked. I promtly upgraded to the PGC version. The PGC gearbox conversion was rock solid once I got it put together perfectly. Its a chuck of billet aluminum machined to accept TM AEG internals. The CA and STAR versions are copies of the PGC gearbox. While not at bullet proof as the PGC, the CA is still quite strong. I imagine you will break a gear or something else way before the gearbox shell breaks. Now the STAR version I would not be so sure about as it is made out of a weaker material (Plastic vs. Metal). In the end, I would chalk it up to "you get what you paid for". And I do not necessarily mean the plastic gearbox cracking - I mean wear from gear axles wollowing out holes and heat from rapid fire possibly warping the plastic just a tiny bit enough to cause feeding issues.
