MAC vs MAC+PHY

One is just a MAC, and needs a separate PHY, the other does both?

Think of the MAC has a higher level, dealing with frames, and the PHY as dealing with the , *ahem*, physical layer - encoding, signaling, etc. In a 10mb Ethernet implementation you might use the same MAC for

These days many devices support only a single type of connection, and there's little or no advantage to a separate PHY, and the integrated device makes your parts count go down.

One is Layer 1, the other is Layer 2.

Having to do integration of a MAC and separate PHY has advantages but you have to then understand the MMI. Hopefully, that's already in the BSP that comes with your eval board and is the same unless your board went off the reservation, in which case...

Given the choice, all other things being equal, an integrated MAC+PHY is the lazy man's way.