I don't have both, but I researched my fair bit into 3d printers so far yet. So this is from my own research but maybe someone who owns them could shine in:
The anet a8 seems to be a worse printer out of the box, it needs a lot of upgrades to become mediocre at best, and if you don't have a lot of experience on 3d printers and fixing them it probably isn't worth it. Unless you like a project and tinkering then maybe it's worth but the costs of the upgrades prolly puts you in a price range to get a different printer anyways.
The ender 3 seems to be pretty decent, doesnt require much work out of the box and seems to be the recommended printer for that price range over the internet, so Personally I would get this one or spend big and get a prusa mk3