Thank you for the comment and advice. I have a Meade tube counterweight system.
Between the two, I would 100% go with the wedge. I think that a de-rotator would add significant complexity with no decent return on the effort. The wedge is far simpler and more reliable. The question you that should be on your mind is "Where are all the images from amateurs using de-rotators?" The lack of them should be a sign for you.
That said, a wedge solid enough, accurate enough, and easy enough to adjust to work well with your fairly large SCT is going to be expensive. The one that you are looking at is $600, but I'm not personally familiar with it, so I don't know whether it will be a good experience for you. From personal experience, I can tell you that if you are going to do any serious imaging, you will likely end up switching to a German Equatorial Mount and a smaller telescope. At that point, the wedge will be collecting dust on your shelf.
If you are building a system primarily for imaging, then I personally wouldn't throw any more investment into what you have. It's a great setup for visual use, but it's definitely not optimized for imaging (which is the reason that you are getting some of the advice above).