Rod Wodaski's book is a good one......not sure if I interpret the author as describing the G11 as mediocre but here's the passage.....
"The Losmandy G11 has been the entry level mount of choice for imagers on a budget for some years. The GM-8 is not stiff enough to be a good imaging mount, but some folks have a good success by putting the G11 tripod and saddle on the GM-8. if your are going to take that approach, you might as well just go all the way and get the heavier G11 head, too. The price difference between the GM-8 and the G11 is not large.
The G11 has larger periodic error than most of the other mounts mentioned here, but you can usually guide out the error satisfactorily if the focal length of your imaging scope is under 2000mm. There is some variability in the periodic and random errors in tracking from mount to mount, and some sites have sprung up with suggestions on how to improve tracking accuracy.
Unguided exposures with the G11 are often problematic due to tracking errors. I recommend using a guider with the G11.
The G11 is a good choice if your on a tight budget, but expect to put in some time tuning the mount and learning about its behaviour under load. The G11 is often spoken of as being capable of carrying 60 pound loads, for imaging, somewhere around 30-35 is more realistic.
Now available in a goto version called gemini, the G11 is excellent for visual observing, and the servo motors of the gemimi may be better for imaging then the stepper motors used in the non goto version."
Quoted from Page 133 The New CCD Astronomy, Rod Wodaski
The other mounts mentioned are from Astro-Physics, Takahashi, Software Bisque, Mountain Instruments, William Yang
If astrophotography is what you want to do the G11 is the minimum I would look at
but I have seen a heap of good work from people using EQ-6's.