The manual on JVC's website indicates official MKV & AVCHD support. So you can playback downloaded movies & camcorder files.

It's not clear though if it's supports streaming over your LAN, or only over the Internet (BD-Live)

Features

• DVD 1080/24p Playback
• Playable Media: BD-R/RE, DVD-Video/-R/-RW, R/ RW, CD, USB
• AVCHD/MP3/WMA/JPEG Playback
• BD Profile 2.0
• HDMI with x.v.Color(TM)/Deep Color
• Dolby Digital /Dolby TrueHD/DTS-HD Decoding
• BD Live Ready
• USB Host
• HD Everio Playback
• HD Audio Bit-Stream Output
• HDMI with x.v.Color(TM)/Deep Color
• Dolby Digital /Dolby TrueHD/DTS-HD Decoding

The JVC XV-PB1 will be available for around 230 Euros ($299) which seems to be a very reasonable price.