If she was refused because the visa officer thought it was a marriage of convenience, then for either the appeal or a new application, you need more and different evidence that the marriage is genuine. That is, more evidence of the same type you already sent in probably won't be good enough.
Depending on the timelines for the appeal and your visa office, one may make better sense than the other.
I would try for a reapplication. In most cases, it will be faster. However, look at the reasons for refusal (in the refusal letter and in your CAIPS notes) and see if you can provide better proof. It may be that you will have to live together for a while before reapplying.
