I'm pretty sure GAB isnt an independantly produced suspension brand/company. Their parts are most likely a combination of KYB (Kayaba Inc; Japan) and Eibach/Bilstein however their products are Finished in Malaysia. They trade under the name RS-One.

Reliability wise I have heard and seen that they are fairly good. However, when it comes to performance (rebound, compression, stroke, ability to hold up against higher spring rates). I don't think they compete very well against Koni, Tein, Endless, Bilstein, Eibach etc... (the Japanese/American/European finished products).