I've been using this player for about 6 months and am generally happy with it. It is a bit flaky and freezes once in a while but it mostly works fine.
The firmware is updatable and the manufacturer has been pretty good releasing firmware updates regularly. Streaming of MP3s and DIVX files works fine, while high-bitrate content like DVD and Hi-Def videos are jerky when streamed over the network. For that reason, I copy media to the unit's internal hard drive (purchased separately). You can copy files from PC to MG-350HD over network, as it has NAS support. I would say that for the money its a great device. It may not be as flexible as HTPC but it only costs a fraction of the price.