I must confirm what has gone before because it's all subjective - it's how you feel about it that matters. However, having owned a 916, 998BP, 998FE and now the 996R I'd say that the thing that matters most is the feel of the engine and whether you need to stand out from the crowd.
If you want character and exclusivisty then go SPS. If you want subtle but brutal power and non exclusivisity then go 998FE. If you want the best of everything then go
996R 