Hi Martha,
This is a bit of a cop-out of answer, but it depends.
One thing to consider before you use Revenue Type for very much is whether or not you're going to want to export the model results. If yes, then I find it preferable to calculate revenue (even if it's sort of a fake calculation" by loading revenue to the ActivityDriverValue Cube, and then allocating it to the CostObjectValue Cube. The benefits of this approach over using the Revenue Types & Revenue Cube are twofold:
1.) You now have Revenue and Cost in 1 cube, so you can structure your line item hierarchy to have a top-level consolidation of Net Margin. This is really desirable, as you can now build a P&L for any Cost Object element with just one Cube (CostObjectValue).
2.) You can now export Revenue and allocated costs back out of PCM for consumption by any downstream tools you wish to use for subsequent BI reporting.
I generally avoid using Revenue Types in most cases, as PCM's CostObjectValue cube seems to perform better than the Revenue cube also. I've found that most things for which you'd consider Revenue Types can also be accomplished via Activity Drivers and the CostObjectValue cube instead.
Mike
