I was curious about the soft image when using 96fps so I did some resolution chart test.
I shot the usual chart to be able to compare the various framerates and see if the other framerates are soft as well.
Lens used is a canon24-105 f4L, no speedbooster to remove that equation.
iso are all at 800.
manual whitebalance.

First I shot 4K at 23.976 as a reference.
For FullHD I reframed the chart since 4K has more crop than at 1080p.
Then first HD shot at 200 Mbps to see if the high bitrate improves resolution compared to 100Mbps.
I also shot at 60P.

Then shot VFR from 2fps up to 96fps.

RESULTS,

200Mbps and 100Mbps Full HD shots resolves the same resolution at around 800+ lines. 24p and 60P yield the same result of around 800+.

Then the interesting part, shooting VFR, 2fps up to 60fps yields same result as non VFR fullHD shots, 800+ lines.
starting from 72, 84 and 96 fps is where the degradation occurs. the softness is aggravated and resolution goes down.

Here is a summary chart showing the vertical res.

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xfp1/t31.0-8/10697401_755871444469923_6714907182978913271_o.jpg

Here's a summary of the center target.

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/10687097_755871427803258_2536485082020010954_n.jpg?oh=104375e75615f33ea2d21885fc9d63b0&oe=54879E38&__gda__=1422651406_7186d857520508cf5096ac8f7ccccd2e

Go here to see the side by side of all the VFR settings.

https://www.facebook.com/media/set/?set=a.755871411136593.1073741834.312706892119716&type=1

Someone mentioned that higher framerates require higher bitrates along with more lumens
For fun Try shooting your baseline test at a 100 bitrate and the higher fps using 200mbs and put more lumens on the chart...just to see/test the theory

VFR is not available at 200 Mbps only at 100 Mbps mode.

This should be expected as the camera has been optimized for 60p recording. Anything above that is cramming more frames into the same bandwidth which would lead to some sort of image downgrade.

This behavior is even mentioned in the PDF manual. I want to know however how low a resolution it is so I can decide how to use this feature.

Further tests I did, due to some suggestions, compared the FHD 96fps with 720p, as some bloggers mentioned it looks like upscaled 720p.

My tests shows that even the camera's 720p is sharper than the VFR rates 72, 84, & 96.

The 720p mode however exhibits more moire than FHD modes.

Links to chart test comparing 720p and FHD 96fps.
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/10418862_756515214405546_7000485577676112982_n.jpg?oh=1a67d4893b5dc0716a3320c9080ce6da&oe=54CC0F80&__gda__=1419791708_30d95edb80c76e117f360c2341e24f4c

center area of chart.

https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/1497673_756515231072211_7355001718035544757_n.jpg?oh=ea655558416c92fa5c2216d2d3813eea&oe=54D0B126&__gda__=1419167343_6115bf3837c20abce45c3029cf6ea1e4

This is also done in MP4 LPCM to see if it's the same as MOV.

At 72, 84, 96fps, the image looks more like SD-DV upscaled.