the main advantage of GPU's is they hold their value long after you are done with them , this is a good project but only for the short term I think due to GPU shortage
I don't think so. Run the numbers and you'll see. I think the main advantage of GPU is flexibility, you're pretty much stuck with XMR if you want to do CPU mining. So you're coming in at a high difficulty level with an important inflection point coming up, in terms of issue rate. But yeah, if you're saying we are at a unique time, I agree. Convergence of high XMR value, lots of servers coming off-lease, GPU shortage, and a brief time left to mine up some XMR profitably.
Don't know whether to thank OP, or remind him that the number one rule of fight club is,
you don't talk about fight club.
LOL yep.
After I posted this on a couple of forums the cheaper used Quanta's, they were $149.00, sold out and the seller on ebay raised these Wywinn servers up about $45.00 but the cpu's are a little cheaper now so thats a wash.
EDIT: Some uptime, the servers are rock solid 24/7 except that I live in the sticks and about once or twice a month the power goes off for a second or two because of storms, winds or whatever.

The biggest plus is not having to mess with them at all since I finalized the setup and got all four nodes running.