Just download both and try doing the same test suite. See which one hurts the least. I'm 99% sure Puppeteer will feel like a breath of fresh air to you.
CasperJS was OK, even better with Nightwatch but Puppeteer is quicker, more stable and actively developed.
That was what I found, as well, for my PhotoStructure tests. It's great to have them driven by gitlab's ci and have cross-platform tests run automatically, and it will be great to now have them run cross-browser, as well.
CasperJS was OK, even better with Nightwatch but Puppeteer is quicker, more stable and actively developed.