I'm spoiled by the viewfinder of the Nikon D3 with magnifying and have to say that the VF-4 very comes close, although you can still see pixels if you concentrate on it. But this impression vanishes quickly and can be neglected in practice. The viewfinder solves enough to in order to make sharp without zoom function can, so it is absolutely practicable. This also means that I can once restricted to the wide-angle end my list of priorities for further MFT lenses, for everything from 28mm prime lens I have in the form of old manual Nikon lenses.
For E-PL5 I have a practical pistol grip, and is ideal in combination with longer focal lengths manual and the VF-4! For example, an adapted old Nikon 80-200 / 4.0 results in a first-class super compact setup for Wildlife. Through the viewfinder you can not only easily focus manually, but it gives the whole system with pistol grip the necessary stability for steady shots at the equivalent of 400 mm focal length of the hand.
The fact that the viewfinder can be tilted upwards for photos from ground level or from chest height, is of interest to all kinds of applications from street photography to macro. Sure, the also the previous model, but the image quality of the VF-4 I do not want to miss. He gives a camera like the E-PL5 a new, high-quality appearance.
A small drawback is that you in the E-PL5 only need to update the firmware (with the supplied USB cable possible!), And that even then no automatic switching between VF-4 and camera screen works. But if you have the viewfinder is activated, and the camera turns off and on again, it recognizes this setting. So you do not turn on the viewfinder separately every time again. Another shortcoming is that the viewfinder no flash photography is occupied at the E-PL5 the hot shoe and so possible. But that has been designed for the fault of the camera, which does not have a built-in flash. Who makes a lot of macro and the like, should be more likely to grab e-P5, whose built-in flash may fire more flashes. But these are all things that are the VF-4 alone can not be blamed, and therefore of course no point deduction.
In short, the most sensible accessory for Olympus MFT system immediately after the kit lens.