Lenovo ideapad z585 or Samsung AMD A-8 laptop?

You probably won't see a huge performance difference between the two, although the Lenovo might be slightly faster. For most everyday tasks it will be a wash.

I personally prefer Lenovo laptops, but buying refurbished is a risk. If you're OK with the risk and you have the time to fully test it as soon as you get it, the Lenovo is a good deal. If you want to play it safe and have the peace of mind that a good return policy affords, buy the Samsung.