It is not often that you find a combination of two items that offer far more together than they do individually. This is called, I think super-additivity, a phenomenon where the combining of two or more ingredients creates a whole, greater than the sum of it's parts.
The Olympus Pen F and 17mm are, to me, a good example of this.
The 17mm has become my go to standard (and wide angle) lens. I have little use for anything wider and tend to think of the 25mm as a short telephoto, so the 17mm, mixed reviews withstanding, is my "everything else" lens, from a portraitist's perspective.
It's main task is what I personally define as traditional street photography, natural (emphasis here) candids of people in sometimes complicated, multi faceted street scenes. Not street portraiture, that holds no appeal for me.
Why it does this so well is a combination of the format's forgiving depth of field and the lens's even more forgiving bokeh. The lens transitions from in to out of focus areas very naturally and gently. The ability to shoot at wider apertures, without the more modern styled and severe sharp/soft fall off that so many newer lenses tend to deliver is a great benefit. I am not afraid to use this lens at f2.8 or even wider for images that require a feeling of depth and layering. Indeed, the bokeh, when at it's most obvious, is attractive and natural. With full frame format or even another lens* in M43 format, I would seldom use an aperture wider than f5.6 and even then lean heavily towards f8-11.
Bokeh is, to me important, but it is not the only benefit the combination offers.
The manual focus/auto focus operation is also brilliant. The Pen F's bright and clear viewfinder, mated to the 17mm lens's forgiving nature allow me to manually focus, often without any peeking needed. I have not before been able to mimic the laser matt focus screen look from my film days which allowed me to manually focus subjects off centre, even in the corners. Being able to view the whole frame evenly, no distractions, with the left eye watching "outside the frame", effectively making the camera invisible, is ideal.
Split prisms and centred viewfinders annoyed as they tend to "focus" (eh!) my attention on the focussing process, not the scene in front of me, much the same as AF.
AF when used is super fast and accurate.
I tend to use the focus by wire option for MF, leaving the clutch manual focus on it's pre set of 5' so I can instantly shoot near without thinking and I find the focus ring in it's normal position with MF override applied to be smoother and lighter to the touch (I can focus with my little finger!). This is one if the nicest and most relevant manual focus experiences I have had in a long time*.
The button on the front of the body activates peeking if needed (white and mild). This does two things. The button is suited to this job as the finger needed to activate it is usually not doing anything else and the button tends to get pushed occasionally by accident, especially with the grip fitted and peeking activation does no harm.
Other things that I like;
The feel is identical from both lens and camera. Cool metal, tight operation and seamless fit. It feels great in the hand, although I still prefer the OMD bodies with longer lenses (mainly the centred viewfinder placement).
The screen can be folded away creating a truly retro, immersive experience. If your desire is viewing with the eye or shooting from the hip using zone focus or "guestimation" then both of these styles will be practiced, used and improved. If there is a screen option also, then there is one more complication, another choice and another convenient excuse to avoid developing superior skills. I actually like the flip out screen because it is a pain in the ass and I don't feel the need to use it!
Utter silence if needed.
Very nice mono. Similar tonal crunch to the Sony NEX7 and very responsive to processing.
Good metering and better highlight recovery. I tend to shoot the OMD EM5 mk1's a little under exposed because their shadows are robust and quite clean, while their highlights (although better than my Canon's when I switched) can get a little lost. The Pen F gets exposure spot on more often and the highlights have about one more stop of detail. This seriously reduces fiddling before capture.
The only things I do not like are the over tight exposure comp dial, but I have also found it (see above) less needed and the lack of a comfortable button under the thumb for AF to give the instant option of AF NOT connected to the shutter button (I liked the idea of AF on the front function button, but it does not seem to offer the option).
There are many refinements in menu and button placement compared to the comparatively geriatric OMD's, but most are lost on me as I have adapted to the older cameras, so I will leave these thoughts to others. Apparently the jpeg files are very good also, but I don't like being locked into limited options by compressed files, so again, look to others for an opinion here.
Could the lens be better? I am sure it could. Most things can be improved, but I would not like any improvements that reduce the existing powers of the lens.
How about the camera? Little things, already worked around. Maybe weather proofing (for both), but Oly cameras and lenses have always shown superior weather sealing even with the non proofed gear (that is to say, they like getting wet about as much as I do).
*The Panasonic 20mm, although looking sharper is guilty of being the polar opposite to the 17mm in both handling (slow AF and tight and "blind" MF) and unforgiving bokeh. It made a nice snap shot lens, producing very sharp looking shots, but was useless for my street work method.