I picked up a Geeetech G2S last November and I'm far from impressed. So far I have:
replaced the hotends with E3D clones, which wasn't strictly necessary but did result in an improvement in print quality
Replaced both extruder drives from plastic (both of which broke with probably < 50 hours on the printer) with aluminum drive mechanisms, which FINALLY made the printer vaguely reliable
Realigned it MANY times - it just does NOT hold alignment.
Finally overnight it died badly during a print. Today it kept powering off. I discovered that the main power connector now looks like this:
Everything about this printer has said "barely adequate to last a few weeks"
I'm done with this printer. I've ordered what looks like a nice i3 clone from Amazon. I'm going to tear this thing down for parts.
I've really tried to use this printer because WHEN it's aligned and working, it does make nice prints. The problem is it only stays working for a few days at a time and I just can't waste my time fixing my tools all the time.