I have a fond spot in my heart for the original. I remember almost getting into fistfights in grade school over which was better: Star Trek, Star Wars or BG. (I went to Catholic school -- we had a 6'2" nun 'Sister Angelica' who we called Battlestar Angelica).
But I watched a large chunk of the marathon that SciFi just ran, and dear god, were some of them bad. Bad in a 'I can't believe I ever watched this' bad. It's not that they are dated, which doesn't bother me (although go watch old episodes of Buck Rogers with Gil Gerard and know why I've largely blocked the '70s from my memories). But the plots are haphazard, with no attempt at continuity, plausibility, or anything. The acting is extremely uneven. I was pleasantly surprised to find that Boomer is probably the best acted and most believable character.
The new series seems headed in a better direction, and I am already looking forward to watching it each week.