Both have their place. They are quite different in features and construction, so hard to compare directly. If you only have the budget for one, go with the cyclorama bacause there is a lot more free and commercial add-ons for it. Both are easy to use, fast to set up but not flexible enough to be called real environments - no matter what the advertising claims. Alternatives to the Cyclorama are around such as Nerd3D's backdrop tool and the Infinity Cove at Runtime DNA, but if you want a real environment system, consider the MicroCosm series at RDNA.