Generally, some of the advantages of the Canon S100 compared to mirrorless interchangeable-lens competitors include: it records higher quality movies (1080p @ 24fps vs none), records high-speed movies (240 fps vs none), has better image stabilization (lens vs none), records movies in 24p and is newer (september 2011 vs september 2008).
However, on average it has a significantly lower resolution screen (461k dots vs 1,036k dots), doesn't have a viewfinder (none vs tunnel), doesn't have a touch screen, doesn't have a screen which flips out and has a marginally smaller sensor (1/1.8" 7.49x5.52mm vs APS-C 23.6x15.6mm).
Panasonic Lumix DMC-GF6
1 year newer
$668 (body only)
Significant advantages of the DMC-GF6 (vs the S100)
- Much higher resolution screen: 1,036k dots vs 461k dots
- Has a touch screen
- Has a flip-out screen
Significant disadvantages of the DMC-GF6 (vs the S100)
- Doesn't record high-speed movies: None vs 240 fps
- No 24p support
- No built-in GPS
common strengths of the DMC-GF6 and S100
- Very good image stabilization:
- Lens
vs - Lens
- Fairly small: Mid size (111×65×38 mm) vs Compact (99×60×28 mm)
- Thin: 1.5" vs 1.1"
Fujifilm X-Pro1
3 months newer
$1,045 (body only)
$1,641 35mm lens
Significant advantages of the X-Pro1 (vs the S100)
- Much higher resolution screen: 1,230k dots vs 461k dots
- Has a viewfinder: Tunnel vs None
- Has interchangeable lenses
Significant disadvantages of the X-Pro1 (vs the S100)
- Doesn't record high-speed movies: None vs 240 fps
- No image stabilization: None vs
- Lens
- No built-in GPS
common strengths of the X-Pro1 and S100
Olympus PEN E-P3
similar age
$450 14-42mm lens
Significant advantages of the E-P3 (vs the S100)
- Has a touch screen
- Has an OLED screen: OLED vs LCD
- Has interchangeable lenses
Significant disadvantages of the E-P3 (vs the S100)
- Doesn't record high-speed movies: None vs 240 fps
- Worse image stabilization:
- Sensor shift
vs - Lens
- No 24p support
common strengths of the E-P3 and S100
- Fairly small: Mid size (122×69×34 mm) vs Compact (99×60×28 mm)
- Thin: 1.3" vs 1.1"
- Light weight: 369 g vs 198 g
Panasonic Lumix DMC-G1
3 years older
$400 (body only)
$480 14-45mm lens
Significant advantages of the DMC-G1 (vs the S100)
- Has a viewfinder: Digital vs None
- Has a flip-out screen
- Has interchangeable lenses
Significant disadvantages of the DMC-G1 (vs the S100)
- No image stabilization: None vs
- Lens
- No built-in GPS
- Significantly heavier: 430 g vs 198 g
common strengths of the DMC-G1 and S100
- Thin: 1.8" vs 1.1"
- Inexpensive: $399.99 vs $197.00
- Each has a built-in flash