We used imgix on last project as a last line of defense against unoptimized images due to the timing constraints of the project. However on greenfield, we would build the image optimization into the build process (could be as simple as few imagemagick commands), and the save pipeline for CMS'ish part (content blocks, adding products etc..) and then just use a dumb CDN.

Imgix really annoyed me as they didnt bother replying about the status page fiasco, this is after we gave them a free-pass with their capacity planning which made us look like idiots recommending them (i.e images loading super slow). Not again, bad ethics.