As has been well documented the sensor and processing engine in the E-PL5 is the same as the OM-D E-M5.
For some posts on that sensors performance see these posts:-
Yesterday I had a look at how the files from the E-PL5 compare to the Panasonic GX1, what might be described as Panasonics comparable camera, with the benefit of full Adobe Camera Raw support.
At base ISO processed from raw, the images are pretty similar. There are slight differences, but nothing significant.
However, at higher ISO's and jpgs. the difference is more marked.
The Olympus files are certainly cleaner. However at ISO 6400, both are pretty terrible. But then does anyone use m4/3 for extensive use at high ISO's in low light?
In terms of an upgrade from a 12MP Olympus Pen, then the E-PL5 does offer advantages in terms of sensor performance. The combination of more pixels, larger files, slightly better dynamic range and high ISO performance, does mean that its a worthwhile upgrade in my opinion.
There are some other improvements I would highlight.
If you use MF, legacy lenses etc. then the magification system is better. Like the OM-D and Panasonic m4/3 cameras, you can now press the magnification button and the shutter release gets you back to the original, unlike before when you had to press the magnification button again, which was always time consuming, fiddly and irritating.
The screen gives that extra option to face you. This isn't just for self-portraits. If you shoot occasional videos like I do demonstrating something then its useful to see what you are recording if you have the camera facing you.
The full manual control over the video gives excellent results. One of the first posts I did on the camera was about the video and I think its very impressive indeed.
Whether or not you think Touch-Screen control, screw-on Grip and extra "Art" filters are an improvement, I'll leave to you. Regular readers will know what I think about those.
All in all I think its a pretty decent upgrade. More useful than just cosmetic and marginal. If for example you want to take advantage of the OM-D sensor but don't want everything else the OM-D offers then the E-PL5 will give you that at about 1/2 the price, and a smaller size and weight.
The E-PL5 isn't going to convince doubters to buy in to the m4/3 system, but then it isn't going to make people leave the system either. If you use m4/3 and you like it then you will probably like the E-PL5 and see it as another option. It brings the Pen range in line with the rest of current m4/3 cameras in terms of the sensor MP count and I see that as a good thing. This sensor certainly does perform better than the current 16MP Panasonic sensor, not by much admittedly, but you can see it.
For me the full manual video control and the resulting excellent footage is the highlight. Though offering a very limited number of options I was VERY impressed by the quality of the footage and this may well be the best I've seen from a camera this size.
See - http://soundimageplus.blogspot.co.uk/2012/11/video-with-olympus-e-pl5.html
Its well-built, looks good and "does the job" better than the E-PL3 so I have no hesitation in giving it a highly recommended rating.
N.B. to see more on the cameras and lenses featured in this post click on the relevant labels (tags and keywords) below.
shutterstock portfolio - http://shutterstock.com/gallery-74596.html
Stock photography by ImagesEurope at Alamy
Stock photography by david martyn hughes at Alamy
Stock photography by david hughes at Alamy