Good slow mo in small form factor

[Martin Matěj]

Hello guys I would like to do some good quality slow motion with my friend to sell on microstock. 

What has better quality? 96 fps 1080p GH4 or 120 fps 720p A7s upscaled to 1080p?

Or are there any other options in this price range or lower for some nice slow motion. I would prefer something more than 60p.

Thanks a lot