Periscope set up to save photos to a folder and to email photos used about 8.5% of CPU (says Activity Monitor), while EvoCam set up to save photos to a folder used about 13.5% of CPU. Aluminum iMac 2.8 GHz, 4GB.

The Periscope interface, definitely more attractive, also seems easier to figure out than EvoCam's.

However, Periscope does not record movies, just photos.

For my purposes, mainly security using the motion detector to store or email photos, Periscope wins. I do not do FTP, so cannot comment on uploading. And I have not used the EvoCam record movie feature.