Lucky I found this tonight, as I'm away on holidays at present! I bought mine in 2010 - I've been very happy with it thus far - albeit limited use given the weather...
Tracking is excellent - guiding graft on PHD shows minimal corrections. I polar align mine using Drift Explorer in K3CCDTools - takes 15-20mins. I have thrown away very few (<5) exposures due to poor tracking (~6-800mm focal length)
Pointing accuracy, once the polar alignment has been done, is pretty good. It's not as good as my LX-90 in alt-az mode, but I'm told that is to be expected when comparing a GEM mount to an alt-az - not sure of why, something to do with geometry and "modelling" by the computers. I'm fairly sure the AP computer doesn't do any modelling to compensate for inaccuracies of alignment. Nonetheless, I am mainly into imaging and don't have too many problems putting objects onto my camera chip. If I have problems, I centre a bright star nearby and "recalibrate" on that before proceeding to the DSO. You need to "recalibrate" after swapping from East to West - but that is to be expected if your scope is not orthogonal to the mount's axis.
The meridian delay feature is excellent - it lets you go past the meridian (or start before the meridian) with your imaging, potentially avoiding the need for a meridian flip.
The review in S&T pretty much says it all. You sort of forget you're using it. I'm a time poor individual, who needs something that just works - it does all I ask in that regard. I've got friends with EQ6's who also produce good results - however, none of us are imaging at >1200mm focal lengths, so we're not pushing the envelope...
Build quality is excellent, even down to the connectors. I have the timber tripod - I couldn't justify another grand for the Eagle.
Any further questions, send me a PM - happy to chat on the phone if you wish.
I, too, own an A-P Mach1 GTO and have been using it for two years or so. It works perfectly. Gotos are accurate as long as you are careful polar aligning the mount. It supports my 45 pounds of imaging gear and tracks accurately enough to produce sub 2 arc second stars when guiding (if the seeing is up to it). It is one of the few mounts on the market whose load capacity for imaging is actually greater than the weight of the mount head itself. If you are looking for a mid-sized, portable mount for imaging you won't find anything better. I haven't had to fiddle with it at all since I got it--no adjustment of gear mesh, no re-greasing, no backlash calibration. It just works every time.
