Hi @arbitrary, I would never buy a refurbished computer from Amazon, eBay, or Craigslist, but I've had very good luck buying refurbished PCs from the Dell Outlet for Work. These come with the same warranty as if they were new, and I've never been able to find a scratch on them. I think in some cases they are surplus that businesses purchased, but then never used, returned them to Dell unopened. These are enterprise-grade product lines like the Latitude and Precision that maybe aren't as impressive specs (on paper) as similarly priced consumer/gaming laptops, but they compensate with better reliability and build quality.
I'm typing this from a refurbished XPS 13 laptop that was only about $800.

For heavy-duty tasks (like rendering) I also have a 15" Precision w/ Quadro GPU. A couple weeks ago, I dropped it on the floor... and the floor broke!
Take this with a grain of salt, but I work in IT, and everyplace I've ever worked, the preferred brands are (in no particular order): Lenovo, Dell, Apple.
@DigitalMan it's good to see a Dell employee here!
(edit) One final thought, is that for your purposes, I would recommend integrated graphics as opposed to a dedicated gaming GPU. For example if I had my choice between Intel integrated graphics vs. Nvidia GeForce GTX, I would choose the Intel (for music production purposes). Reason being, drivers.