What speed are the adapters rated for? There are three standards, HomePlug 1.0 (14 Mbps), HomePlug 1.0 Turbo (85 Mbps) and HomePlug AV (200 Mbps). I have the 85 Mbps type (from Directv) and they seem about as fast as a hardwired connection (which is much less than the 100 Mbps it is rated for, typically around 40-50 Mbps).
None. Could be something interfering in the line maybe, dunno. Itll work out fine, Ill use my wireless gear for the Vudu box and put my HR20 back on the powerline. I uses its VOD very rarely right now.