[Kevin Sevcik]

Our team has used extruded aluminum as well. About the removing nuts problem... we milled bigger slots into the slots so we could drop the nuts in without detaching everything and it worked relatively well.

While it is, indeed, very rigid and durable, it's not the best strength/weight option out there. A simple hollow square aluminum extrusion with the same weight per linear inch is going to be stronger than an extruded profile like this, because it will have all its mass at the outer extremities of the profile instead of wasted in the middle.

My current opinion is that it's great for prototyping or for a team without access to aluminum welding, but plain square tubing should be used if at all possible.