The following pro's and con's ar my view:

SUMPRODUCT is

- leightweight
- formulas only

Pivottables

- drilldown
- external data source(but this can be partially mitigated with getting
the external data into an excel sheet first)
- OLAP source
- drag & drop customization
- nested hierarchies
- 'on the fly' slice & dice
- VBA support

when you only need a "simple" static pivottable with not much
interaction, SUMPRODUCT will do, in other cases a pivottable is better.

DM Unseen