We did rewrite some of the G/L reports in Crystal (Balance Sheet, Income Statement, various expense statements). I say we but actually it was a financial analyst here. The RDA version of the Balance Sheet (a customized version modified by a consultant) took 45 minutes to run and killed our server while running. The Crystal version runs in 45 seconds.
I can say it would have been very difficult for me to write the financial reports because I'm really not a financial sort of guy. For the guy who knew his financial stuff and was trained in Crystal it took him a week or two (it was one of his first reports) and isn't very pretty internally but it runs great.
yes - data selection and grouping is very flexible.
Our Analyst decided to use G/L categories assigned at the Object Account level (or it could done at a Business Unit level or combination of the two - depending on the company) to assign Crystal Groups to corresponding to the Level of Detail. We (Wagstaff) only needed 3 levels of detail, but JDE allows upto 30 categories ... He can generate reports very quickly now.
I am forwarding to your email address my response to a similiar question some years ago that has more detail to it. Hopefully this will guide you as to what can be done.
Regards