I was looking to upgrade my portable imaging setup and couldn't decide between the SX and the GM8 - so I purchased both s/h, with the intention of selling one later.
I have used a SP with modified controller to take guided images sucessfully in the past, but I wanted something I could use with up to 1000mm efective focal length and the drives of my old SP are just not up to that.
Having a G11 already (just too heavy to be portable) I expected the GM8 to be good, but I could not justify the huge additional cost of the Gemini system so I wondered whether a SXW would fit the bill. If you want to maximise your imaging time then GOTO is almost essential. I reckon I wasted several hours a night when on hol in the southern hemisphere with the SP tracking down objects and then swapping the eyepiece for a camera once I had found the object.
As expected the GM8 works brilliantly. The build quality is good, the drives are excellent and the polar finder (I don't have one on the G11 which is permanently mounted) is a revalation - it takes 2 mins to get the mount on the pole. I cannot speak too highly of this scope - it is far the best I have ever used. The downside of the mount is, of course, the weight. The GM8 is far too heavy to contemplate taking on flights abroad.
When the SXW arrived the difference in quality was startling. Balance with any load was not a problem - in fact you couldn't balance it! The shafts were so tightly gripped that a fs102 could be held in place without a counterbalance weight! So I stripped it down to establish what the problem was. Joining the SX group told me this is a common problem if not a universal one. Smells like zero quality control to me. I was not impressed by the slop in the gears and read that I could expect changing direction in dec could require the motor to be run for several seconds. No matter what I did with the dec drive I could not get this below 4 seconds at guide speed. This is just rubbish design I am afraid. There are too many gears in the drive chain.
Now for the mount in use. I found the SX polar finder almost inexplicable and very fiddly in the dalight. It is quite impossible to use (as intended) in the field. In the end it is quicker to use it like the old faithful SP polar finder and ignore the many concentric wheels you are supposed to align.
Once on the pole I found the alignment setup a bit odd - but ok. The good news is that the GOTO works fine. When I tried taking images it soon became apparent that the time spent on getting the mount well aligned to the pole had been wasted. Only by offsetting the mount from the pole to make sure the dec guiding direction didn't change during an exposure could I get anything approaching round stars.
After using the SX for a couple of months I can honestly say the simpler SP is just as good an imaging platform - if you are using an autoguider, that is.
If I had not already had other mounts to compare it with I might have concluded the SX was an acceptable platform as I have been able to achieve 5 minute exposures that have yielded round stars (albeit with focal lengths of 500mm or less) However, I believe the hype about this mount disguises some basic mechanical flaws and poor quality control. I recomend anyone contemplating a SXW/D mount should read the postings on the SX yahoo group. If you want a compact portable mount for visual use they perform well enough, especially once you get to grips with the Starbook.
The one thing the SXW mount has done is make me somewhat less critical of my old LX200 mount as an imaging platform
