Over the recent years it was sometimes difficult to understand Olympus' DSLR marketing strategy but recently they got their act together with a pretty straightforward lineup starting with the budget-class E-420 & E-520, the "prosumer" E-30 up to the professional grade E-3. Only the feature gap between the E-520 and E-30 was a bit deep and consequently Olympus released the new E-620 to fill it. In terms of handling, build quality and pricing it is still a consumer DSLR but it has also inherited much of the technology used in the E-30.
Major improvements over the E-520 include ...
a new 12mp Live-MOS sensor
a glass-fibre reinforced plastic body
7-point AF system with 5 cross-sensors
a better viewfinder, the viewfinder LCD display sits below the field view now
a tilt-swivel LCD monitor.
The Olympus E-620 is available in various packages such as body-only (~600€) or, probably the most attractive option, with two kit lenses (14-42mm f/3.5-5.6, 40-150mm f/4-5.6) for less than ~800€.
So within the Olympus system it appears to be a natural winner but it makes sense to look on the other side of the fence. Here's a little key feature comparison vs the direct competitors in the E-620 camera class:
DSLR
Olympus E-620
Nikon D5000
Canon EOS 500D
Sony Alpha 380
Format
Four-Thirds
Nikon DX (APS-C)
EOS (APS-C)
Alpha (APS-C)
Sensor size/type
17.3x13.0mm, Live-MOS
23.6x15.8mm, CMOS
22.3x14.9mm, CMOS
23.6x15.8mm, CCD
Sensor
12mp, 12bit
12mp, 12bit
15mp, 14bit
14mp, 12bit
"Crop" factor
2x
1.5x
1.6x
1.5x
Sensor dust-removal
ultrasonic
ultrasonic
ultrasonic
low frequency sensor shake
AF Sensors
7 (5x cross-type)
11 (1x cross-type)
9 (1x cross-type)
9 (1x cross-type)
Image Stablizer
sensor-shift
lens-based
lens.based
sensor-shift
Metering
ESP, center-weighted, spot, Hi-Key, Low-Key
3D matrix, center-weighted, spot
35 segment, center-weighted, partial, spot
40 segment, center-weighted, spot
HD Video
-
720p
720p + 1080p
-
Live-View
yes, tilt-swivel LCD monitor
yes, tilt-swivel LCD monitor
yes, static LCD monitor
yes, tilt LCD monitor
Viewfinder
pentamirror (95%, 0.96x)
pentamirror (95%, 0.78x)
pentamirror (95%, 0.87x)
pentamirror (95%, 0,74x)
Size
130x94x60mm
127x104x80mm
129x98x62mm
128x97x71mm
Weight
515g
590g
520g
529g
The E-620 compares favorably here but, to be honest, it doesn't really offer any unique features or aspects beyond the mainstream. If anything it appears to avoid a obvious weakness except, maybe, the lack of a HD video mode (if you count in the sub-optimal implementations by Canon & Nikon).
The four thirds gang often emphasizes the size and weight advantages compared to their APC-C counterparts. However, when looking at the sheer camera specs this isn't really obvious when considering the camera only - the E-620 is just as small as the EOS 500D for instance. However, there's some truth in this statement when looking beyond the camera towards the system lenses. The Olympus Zuiko 40-150mm f/4-5.6 ED is much smaller (65.5x72mm, 220g) than e.g. the already very compact Nikkor AF-S 55-200mm f/4-5.6G VR (73x99.5mm, 335g). The size advantage is naturally even more pronounced when comparing 4/3 lenses with their full format counterparts (e.g. Olympus 50-200mm f/2.8-3.5 ED vs Canon EF 100-400mm f/4.5-5.6 USM L IS).
And after all the babbling ... here're some views of the E-620:
