As someone new to astro imaging and quality EQ mounts, I'd logically agree with Ed's comments.
I've seen some excellent images from an EQ6 (or less) mount, provided the mount was accurately polar aligned, drift aligned, well balanced, and not over laden, and then guided using something like phdguide. Some of these images rival those taken by more expensive mounts. I've seen some average imagers with very expensive equipment taken well, let's just say, not very good images.
Take care with how you set things up, treat the mount well, and a cheaper mount will perform. Is the CGE worth 3 times the price? imho, no. Not unless you image with heavy loads that are beyond the ability of the EQ6 to handle.
I've found that Astronomy is like hi fi - it's a big you know what contest about who has the biggest, or most expensive piece of kit. Half the people with expensive setups probably don't really use them, or use them very well.
I just purchased an Atlas (upgrading from a ASGT) so I just answered the Atlas vs CGE question. To me the comments concerning the CGE being the minimum to get into serious imaging are a little bit of a stretch. I have seen some absolutely high quality images produced using "lower" grade mounts. The big difference to me was the capacity. Yes the CGE has higher weight capacity and if that was the determining factor in image quality I would agree that the CGE is better. We all know that there is more to it than that. The skill of the operator is a much larger factor. I personally did not need the capacity at this time. Since astronomy equipment holds its value exceedingly well (>80%), I don't need that much capacity and my skill is still growing, there was no reason to spend that much money. In addition my imaging targets are wider field where I don't need the super high accuracy.
I bought a used Atlas. If I need to step up in terms of capacity then I can sell the Atlas without taking a huge hit and buy the CGE.
As with most of these things there is never a right or wrong answer. It all depends on money and what you want to do.