Depends a bit, Graphene will usually provide a bit extra to the security update period but for my cheap self it usually comes down to how long a particular device will be supported vs how cheap I can get it. https://support.google.com/nexus/answer/4457705?hl=en#zippy=%2Cpixel-a-g-pixel-pixel-a-g-p...

Pixel 8 has the best security with hardware Memory Tagging support. A Pixel 7a is the best for value and lifespan. A pixel 6a is the cheapest of all supported devices with more than a year of support left. Worth noting Google is making an announcement for Pixels in a few days... Pixel 8a? How long...