network adaper speeds tend to be quoted in mbps either one way or 2 way (duplex).
a 100 mbps lan adapater is standard fare with 1000 being gigabit ethernet.
Homeplugs come as 14, 85 and 200 mbps at the moment. The 200 units quote a theoreteical use a duplex speed to get to 200, it arguably should be 100.
In practice none achieves the same throughput as a cheap 100 mbps etherner cable an adapter but they are usually much simpler to use, more reliable and importantly for my gaming more consistent than any wifi.
85 mbps units are very cheap at the moment, and more than up to the job for 2 mbps or much higher internet connections.