There are really two questions here, one is about the mount, the other is about astrophotography.
The mount:
This mount will handle your XT10. Furthermore, for visual observing, tracking will greatly enhance your capabilities.
You can also get tracking by putting your Dob on an equatorial platform. An equatorial platform, however, is not good for deep sky astrophotography because of "field rotation," which is demonstrated as well as I've ever seen it, with moving videos, in the link below.
When you put a Newt on a go-to equatorial mount, you will want to change the position of the eyepiece depending on what part of the sky you are in. So you don't just need rings. You need *rotatable rings* and should inquire as to whether your choice suits the need. Otherwise you should contact Parallax Instruments. Fancy rotatable rings use ball bearings to have an inner and outer ring; the less fancy style lines the rings with felt which often is enough to allow the scope to be rotated.
Every scope has an *optical axis*. The optical axis of the scope is not usually perfectly aligned with the tube. Usually that doesn't matter. However, when you have a go-to system, the system has "expectations" as to where the optical axis is. But you are rotating the optical axis to get at the eyepiece. The computer won't know you're doing that. So the accuracy of your go to movement (your "slewing") will be diminished, perhaps even substantially diminished, compared to a refractor or an SCT.
The stability of a Newtonian on a mount is related to the *moment arm* or leverage of the system as a whole. That means that your fat ten inch tube will present a significant surface area to the wind, and the long tube will have sufficient leverage that the shaking may be exaggerated which could, on some nights, frustrate your astrophotography ambitions.
Related to this is the problem of *balance* of the tube. It has to be balanced in both axes. When you add imaging equipment you will need an extra counterweight on the Dec axis. But you will *also* need to alter the position of the tube in the rings: if you add weight to the eyepiece area you will need to slide the tube "down" which could cause clearance issues in the legs. If you counter the extra weight by putting more weight at the bottom to move the scope up, you will need to add still more weight to the dec axis. And you may end up exceeding what the mount can reasonably handle.
I could write more about the issues but suffice it to say that for a 10" Newt I would recommend at least a Losmandy G11 and possibly an AP900 if you are serious about astrophotography. Because astrophotography is all about the mount.
Astrophotography:
Now, speaking of which: if you want to get into astrophotography, you have two domains: planets and the moon, and deep sky (galaxies, globular clusters, etc.). These are two completely different endeavors. For planets you will need a good webcam which will take thousands of images at very long focal lengths. Your XT10 is not the best choice for this. It may work OK, but you are working against the engineering of the scope: it has a *short* focal length, which you will need to barlow up about 3 to 5 times, and a *long* physical length, which decreases your imaging stability. So if you want to do that you should probably get a c8 or a c9.25 SCT: there you get *short* physical structure (maximizing stability) and *long focal length* (optimum for planets).
As a general rule, deep sky photography, by contrast, is extremely demanding of the mount. You need a minimum of periodic error, and a minimum of of other tracking errors (polar alignment) and a minimum of shaking. For these reasons, people who are learning to do *deep sky* often select 80 to 102mm refractors because these short focal length instruments (specifically the expensive apochromats) because these scopes are most tolerant of mount tracking errors. The longer your focal length and exposure times becomes, the more you need a superb mount. And the mount you are looking at is merely "pretty good." But that mount should be fine with a 4" or 5" refractor. Regrettably, the bad news is, in order to avoid sever color aberration with a refractor, you need an expensive triplet.
So it seems to me you need to consider what your needs are. The German equatorial is not the only way to get tracking. If you want to do photography, you need to think deeply about planets vs. deep sky. Your Newtonian *can* be used effectively for deep sky, and some people do in fact take an inexpensive tube and mount it on a humongo $15,000 mount like the Paramount ME. But the bias in photography seems to be apochromatic refractors for deep sky and SCTs for planets, but most of the serious Newtonian astrophotographers I know have migrated to very, very expensive mounts.
An inexpensive mount like the one you're looking at may be an exercise in frustration but at least when you $3000 to $10,000 for you 2nd mount you'll know why. And remember, you read it here first!
Incidentally these kinds of discussions really don't work on yahoo. Try astromart: pay the $12 (one time fee) and get access to tons of good quality equipment and discussion forums. Also try Cloudy Nights, excellent discussion forums, the most active on the net. But, the Cloudynights used market is about 1/20th the size of Astromart's, and Astromart is much better policed against fraud.
Hope that helps
GN
Edit: Newtonians on GEMs do not use slings, they use mirror cells, and are supported equally from all sides. No slings involved. The mirror cell on my 10" mirror works quite well. It is certainly the case, however, that my ten inch Newt on a German equatorial mount requires more gymnastics to reach the eyepiece than any of my other telescopes. The Orion XT10 uses a primary mirror cell which is different from the slings used by some, but not all, high end Dobsons. It should be OK in an equatorial configuration. I've included a link to a picture of the mirror cell of the XT10.