They are both listed for $299, but deals may be available.
Differences: -100 runs cooler. RF remote works better on -700 (internal antenna) than on -100 (external antenna). -100 had both optical and coaxial digital audio. -100 has second network port (I don't know if it is functional). -100 may have a slightly larger hard drive (I haven't verified this). -700 has newer software if you participate in CE program. -100 made by Thomson (RCA); -700 made by Pace.