I’m having the same issue with your plugin and Subscribe2. P3 reported 52% .7166 seconds for WYSIJA. I also use Subscribe2. It was the second highest resource hog at 26% .3589 seconds.
Really love your plugin and hope you can resolve it. Furthermore, it would be AWESOME if you could add the features to your plugin that I am having to use Subscribe2 for…. it sends post/page notifications and allows users to subscribe/unsubscribe to categories and authors.
I tried to create a single Mail Poet daily newsletter that combined the posts each user was interested in, but couldn’t work it out. Would LOVE to do it all with a single daily email from just your plugin!
Thanks!