I've been downloading concerts off of various web-sites, and sometimes it takes awhile to download. I've downloaded for more than twelve hours to get a show. You're going to have to get a Bit torrent program, I use BitTorrent, I find that it's easy to use, and the new 6.0 program is very good. ABC BitTorrent is another program that's good. I haven't download off Dead.net, but Lon has, so maybe he'll pipe in with his thoughts. I'm really enjoying downloading the various concerts, there are some outstanding quality d.l.s out there, so buy yourself a couple of hundred blank cds, and have fun.
Actually, to my knowledge, I haven't downloaded flac from dead.net nor have I ever done flac; when I had the time I didn't have enough highspeed and never mastered the process.
I have purchased all the "Digital" Dead official releases featuring the band through the Godchau years, but from iTunes.