I figure the newest of roll cage tubing should have a thread here. Its been around just over a year now, cleaner, welds better and is stronger. However it costs more, I read an article in Circle Track on it.
http://www.aedmotorsport.com/catalog/product/docol-tube-r8
http://www.aedmotorsport.com/catalog/product/docol-tube-r8