BD670 a month ago and so far I have been satisfied with my selection.
BD670 plays blu rays with no issues. Load time is instantaneous. For less demanding discs load time from inserting disc to title screen took ~1 min and for BD Java heavy discs took about 1 min 45sec. Since I have a pioneer plasma, I've set playback at 24hertz with no issues. Supposedly the BD570 had stuttering issues. Video and quality of sound are excellent.
I primarily purchased this player though for network streaming support. Up to now I have played avi and mkv files with no problems. Playback is quick and I was impressed with both picture and sounds quality. BD670 offers dual band frequencies therefore if your loved ones are using bandwidth, your bluray player can still stay smooth by using other frequency (assuming your router also possesses dual band capabilities). Warning to heavy quicktime users, the player are unable to play content with the extension MOV. MP3 and photos have played with no hitch.
Network setup took me a few minutes. You can either use the program that is included with the player and install Nero Home Media Server essentials or perhaps manually share folders and wish that your computer systems pop-up properly. I'm still figuring out the kinks. To log onto a computer manually, you click the computer name, a menu labeled CIFS appears requesting your user name and also password. You will have to create a user profile on that corresponding computer. Enter the same user name and password and you will be in.
LG Applications seem to have been very limited so far and a big strike on this player right now. I was looking forward to Amazon VOD and Hulu, but they are not available yet. Allegedly there is a big update March 25th which will enable these applications, but I am just consuming the rumor with a grain of salt.
In general great player with networking capabilities. It's ability to play a wider variety of content with no size restriction is the primary good reason why I went with LG BD670 versus Sony, Samsung, or Panasonic.