At the end of last week, I received P10 and CX4 and since then I'm taking photos with them and working on some comparisons. Here are some first crops.
First 28mm crops. All cameras were set to Standard settings and Spot AF.

- p10_cx4_cx3_cx2_center.png (481.99 KiB) Viewed 6655 times

- p10_cx4_cx3_cx2_lbottom_corner.png (510.32 KiB) Viewed 6635 times

- p10_cx4_cx3_cx2_rtop_corner.png (478.48 KiB) Viewed 6588 times

- p10_cx4_cx3_cx2_building.png (462.98 KiB) Viewed 6576 times

- p10_cx4_cx3_cx2_trashbins.png (520.04 KiB) Viewed 6537 times
As you can see, P10 appears to deliver sharpest photos and best corner performance at 28mm. Although the P10 lens construction (number of lenses, coating and positions) should be similar or the same as CX3/4 lens, it's evident that the lens assembly is different. In my opinion, it also explain why the P10 module is much thicker than CX body? This not only allows to start the P10 faster than CX (because of less time required to extend the lens) but it also noticeably improves the corner sharpness. At least at the wide end
I'm not quite sure about 300mm comparison. As you can see below, the P10 crops look a bit less sharp than CX4. I think it's caused by Spot AF where the P10 shot was slightly front focused. I will probably redo this comparison with all cameras set to Infinity.

- p10_cx4_cx3_cx2_tele_center.png (441.74 KiB) Viewed 7692 times

- p10_cx4_cx3_cx2_tele_lbottom_corner.png (422.74 KiB) Viewed 7656 times
Below you can check the colors (all cameras were set to Daylight WB) and overall exposure. P10 and CX4 are very close to reality. CX3 is surprisingly most overexposed at more or less the same shutter speed.
28mm

- P10 DNG
- R1099507_dng_sm.jpg (583.32 KiB) Viewed 6221 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 3:30 pm
- Focus length: 4.9 mm
- Shutter speed: 1/810 Sec
- F-number: F/3.5
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GXR P10
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- P10 JPEG
- R1099507_sm.jpg (543.84 KiB) Viewed 6202 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 3:30 pm
- Focus length: 4.9 mm
- Shutter speed: 1/810 Sec
- F-number: F/3.5
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GXR P10
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- CX4
- R1061204_sm.jpg (551.35 KiB) Viewed 6226 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:16 pm
- Focus length: 4.9 mm
- Shutter speed: 1/810 Sec
- F-number: F/3.5
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX4
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- CX3
- R0012651_sm.jpg (554.36 KiB) Viewed 6212 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:15 pm
- Focus length: 4.9 mm
- Shutter speed: 1/870 Sec
- F-number: F/3.5
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX3
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- CX2
- RIMG0005_sm.jpg (509.42 KiB) Viewed 6209 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:10 pm
- Focus length: 4.9 mm
- Shutter speed: 1/870 Sec
- F-number: F/3.5
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX2
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average
300mm

- P10 DNG
- R1099505_dng_sm.jpg (572.67 KiB) Viewed 6394 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 3:29 pm
- Focus length: 52.5 mm
- Shutter speed: 1/570 Sec
- F-number: F/5.6
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GXR P10
- Exposure program: Normal program
- Exposure bias: -7/10 EV
- Metering mode: Center-weighted average

- P10 JPEG
- R1099505_sm.jpg (477.6 KiB) Viewed 6235 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 3:29 pm
- Focus length: 52.5 mm
- Shutter speed: 1/570 Sec
- F-number: F/5.6
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: GXR P10
- Exposure program: Normal program
- Exposure bias: -7/10 EV
- Metering mode: Center-weighted average

- CX4
- R1061207_sm.jpg (488.04 KiB) Viewed 6195 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:17 pm
- Focus length: 52.5 mm
- Shutter speed: 1/540 Sec
- F-number: F/5.6
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX4
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- CX3
- R0012653_sm.jpg (461.81 KiB) Viewed 6162 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:16 pm
- Focus length: 52.5 mm
- Shutter speed: 1/620 Sec
- F-number: F/5.6
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX3
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average

- CX2
- RIMG0007_sm.jpg (458.48 KiB) Viewed 6149 times
- EXIF-Data
- Image taken on: Tue Oct 12, 2010 4:11 pm
- Focus length: 52.5 mm
- Shutter speed: 1/540 Sec
- F-number: F/5.6
- ISO speed rating: 100
- Whitebalance: Manual
- Flash: Flash did not fire, compulsory flash mode
- Camera-model: CX2
- Exposure program: Normal program
- Exposure bias: -3/10 EV
- Metering mode: Center-weighted average
I will upload full resolution shots tomorrow.