We also had issues deploying nodes - both turned out to be switch issues:
First issue was machine would boot via PXE, but had IPMI connectivity issues on MAAS server - ended up only half ports on original switch had POE.
With supermicro if you don't see the BMC POST on booting for IPMI then the deployment will not work.
Make sure all ports on your switch support POE.
Our second issue was related to commission timeout - which was DHCP related. We changed setting on cisco switch to make dhcp pass through quicker: