P500, S9100 and L120
Firstly L120 is out of my list, why? it needs 4 x AA batteries.
It doesn't use Rechargeable Li-ion Battery.
Now for the remaining P500 and S9100
Both Share the following:
• 1/2.3" Type CMOS
• 12.1 million effective pixels
1080p HD movies with stereo sound
ISO sensitivity 160 - 3200
LCD monitor • 3.0 inch tilting LCD
• 920,000 dots
• Wide viewing angle TFT LCD monitor with anti-reflection coating
• 5 level brightness adjustment
Storage • SD/SDHC/SDXC
Connectivity • USB 2.0 Hi-Speed
• AV out (PAL / NTSC switchable)
Now main differences:
Even thought P500 has bigger zoom lens it's wider than S9100 and faster.
(35mm equiv) P500 22.5-810mm, S9100 25-450mm
P500 F3.4-5.7, S9100 F3.5-5.9