I agree that a 10" or 12" RC is not exactly a beginner's scope for learning imaging, but that doesn't mean you can't be successful, and the scopes can be very rewarding longer term. Here are the problems for a beginning imager (which I assume you are, but please correct me if that's not so):
- Imaging at 2,000mm to 2,500mm is really hard. Your tracking must be perfect to get round stars. Your seeing needs to be good for the image to not look soft. You better be using a high quality mount if you are working at 2,000mm focal lengths and above (or at least one you have fully optimized). This is nothing specific to Ritcheys--it would apply to any scope at these focal lengths.
- They are, indeed, more challenging to collimate than most scopes since you have two aspheric mirrors. That means you need only need to get the tip/tilt correct for the mirrors, they need to have their optical centers on the same axis. With an SCT or a CDK, for example, if the secondary is not exactly on axis it just changes the field illumination a touch. Not really a big deal since a good flat will address this. However, with an RC you will introduce off-axis coma. All that being said, there is no reason the collimation can't be quite stable with these scopes. I used a 10" RC for a while and it would hold collimation even when transported in a car over bumpy roads, at least most of the time. Just expect a learning curve.
- If you were thinking of visual use as well as photographic use, I think there are better choices. The GSO Ritcheys can do very well for photography, but I was never satisfied with the visual, likely because of the size of the central obstruction. Contrast is quite low.
- You'll need a lot of integration time to go deep at f/8, and you'll want to go deep since the objects these scopes are typically used for are galaxies with the occasional globular, or planetary nebulae sprinkled in. Some smaller emission nebulae as well. You want to capture tidal tails around galaxies? Galactic cirrus/IFN? Reflection nebulae? Dust, dust, and more dust? A large scope with a long focal length is a great choice. It's just not an easy choice. Expect multiple hours of exposure time per image.
Basically, if you are as happy optimizing your scope as you are collecting data, if you get as much joy from the experience of producing an astrophotograph as you do from the photograph itself, if you don't mind creating only a few really good images per year (depending on your seeing conditions), if you really desperately want to photograph galaxies, not just larger objects then a 10" or 12" Ritchey is a very good choice. Expect a long and steep learning curve, both for optimizing the hardware and data and in processing.
I would recommend one of the truss scopes rather than a solid tube. In a 12" I don't think you have a choice. In the 10", you can get either design. Normally I would recommend a solid tube since it prevents heat rising through the optical path, but the solid tube GSO scopes have a peculiar design for the focuser attachment that can lead to collimation issues with flexure, especially with heavy cameras. I never had that problem with mine, but lots of other people have run into problems. Stick with the truss.