Verdict

The Olympus E-620 is a vast improvement over the existing consumer grade E-series DSLRs. The new viewfinder has received a major revision - while not as good as the ones used in the E-30/E-3 it's bigger and better than the "tunnel view" that we've seen in the past in the E-3xx/4xx/5xx and the viewfinder data display has been finally positioned at the bottom rather than to the (odd) right side of the screen. The (phase detection) AF system has been modernized to current industry standards. The articulating display is more than useful for LiveView-based compositions. The E-620 is a very compact DSLR and combined with the two pretty good "kit" zoom lenses it is about as small and light-weight as it gets in the DSLR world.
So is everything rosy now ? Unfortunately there're still some down-points compared to the strong competition in this segment. The pixel-to-pixel resolution potential is rather mediocre due to a strong AA (low pass) sensor filter. This may be favorable when it comes to reducing moirees but Olympus went too far here. In order to overcome the resulting image softness Olympus applies some rather heavy default sharpening. To be fair - the issues above relate to the RAW file potential whereas the straight JPG quality is actually as good as the competition. The increased noise level is compensated by quite efficient noise reduction.
Another problem is the handling concept of the camera. Possibly it's just me but using the control dial on the top of the camera is inconvenient at best. All other manufacturers use a front- and/or back- control dial which can easily be operated by your forefinger or thumb - a top dial is far more cumbersome. This is insofar strange because the Olympus E-3 and E-30 use the conventional font-/back-dial approach and it can't be such a bad thing when they use it in their top DSLR models, right ? The camera has an immense set of features but I had the impression that it has traction problems here because it simply doesn't get all this power onto the road with too many features hidden in some sub-menus.
All-in-all the E-620 is an interesting new alternative in this camera segment. Its major strength is the extremely compact design especially when taking the two kit zoom lenses into account. During the field tests I met some people who sponatuously approached me with "now that's a small DSLR" so Olympus has obviously hit a sweet spot here. The camera is an obvious choice for existing Olmypus users who'd like to upgrade from their old consumer DSLRs. When looking on the other side of the fence things are more tricky because both the Canon EOS 500D as well as the Nikon D5000 are strong rivals ... probably too strong.