I have the 6.5x version of the Papilio II (the newer, fully-multi-coated one).
As others have noted, the key point of these binoculars is their close-up viewing ability - at which they excel; providing bright, clear views with good contrast and well saturated colours, to a very close minimum focusing distance. They are obviously great for viewing insects (hence the name) and other "bugs", flowers and anything else close by which you might want to see magnified. The other side of this optimisation for close-up viewing seems to be an only-OK view at longer distances (say, 30M/100ft to infinity). Not bad, mind you, but just OK.
My Papilios provide a decently wide field of view, but certainly not expansive (I went with the 6.5x rather than the 8x as I suspected the FOV of the latter would be to restrictive for me). The "sweet spot" for focus seems quite wide as a proportion of FOV, with only gradual degradation towards the edges. Chromatic aberration is a different matter, being well controlled in the centre but becoming apparent fairly soon off-axis, though never becoming especially intrusive (but do note that I'm not particularly sensitive to CA).
Flare seems quite well controlled, including veiling flare. This is probably because the Papilios are constructed with deeply recessed objective lenses, with what seems to be a flat pane of coated glass near the front of the binocular to protect from dust etc. Note that this protective pane looks quite susceptible to scratches in the coatings or even the glass (mine arrived with a small coating scratch, albeit one that causes no apparent problems). Another obvious aspect of construction is its reverse-porro-prism design, which aids overlapping views at close focusing distances while potentially reducing the contribution of objective separation to "3D effect" (which I find quite decent, regardless, especially when close viewing). Overall, the Papilios seem fairly well constructed within the constraints of their light-weight, small-sized, plastic body and small optical elements. However, they don't seem as if they would stand up well to harsh use (unlike, say, my other small bins: Vortex Diamondback 8x28s, which seem very rugged).
The focus wheel on my Papilios seems precise, but requires little force to move and is easily nudged off-position. Focus is clockwise to infinity (I have no preference for or against clockwise or anti-clockwise focus.) The eyecups are small, with three positions (call them down, middle and up). I've found the eyecup setting, inter-pupiliary distance and diopter settings critical to getting a decent view through my Papilios, along with more care in eye position than I'm used to - perhaps because focusing up-close and personal is less forgiving. I've found I need to use the middle eyecup position with glasses, while having them fully up without. I also need to move IPD slightly when changing between with/without glasses use. I've also found that I need the diopter position wound somewhat in the "+" direction. [With most binoculars I use eyecups fully up and a neutral diopter setting both with and without glasses. Note that I am near-sighted; ie. I need glasses for distance vision rather than close-up.]
All told, I'm very happy with my Papilios. I think they give great performance for their price, allowing that they are more for specialised close-up use than for general usage.
...Mike