They aren't lighter but they are chrome bars and have a superior finish.
Also they make a variety of different sized bars.
I personally like their 15/16" diameter John Hughey bar.
It is somewhat hollowed out and weighs about the same as a 7/8" bar.
Erv
I have 2. There is something special about the finish making them so smooth. I use a Hillman bar or the poly bars for my typical playing. I have had my son try all my bars and he chose the BJS. His knowledge about them is limited but he felt they were a better feel on the strings.
I was recently listening to Paul Franklin talking about BJS bars. He uses a 7/8 diameter bar, and he says it's the bar many players use. I think Teddy Carr, former Ricochet steel guitarist used a BJS bar at one time. I was looking at the BJS website not too long ago, and it gives great descriptions of bar sizes and how the bars work, whether you play steel, dobro, or lap steel. The website tells what bar sizes work best on any steel guitar.