As well as benchmarks, there's this document that guides you around the NXP website:

http://www.standardics.nxp.com/literatur...system.pdf

Although it's focussed on the ARM-based chips, the website structure is pretty much the same for the 8051-based devices.

It tell you:

Where to find the Microcontroller parametric selector (p15);

Where to find the Microcontroller sections in general (p17);

Where to find the Microcontroller Line Card (p19);

Where to find the Microcontroller Data Sheets / User Manuals / Errata sheets (p21);

Where to find Literature / Application Notes / Articles / Tech Notes (p23);

Where to find Design Examples (p26);

etc, etc,...