Synopsis: Five samples of different foams were compared by density, durability, and legality.
Density: Measured by cutting samples, taking precise measurements using a calibrated digital caliper, and using a gram scale. Accuracy deemed to be within 10% using manufacturer provided densities.
Crush Durability: Measured by compression testing. Initial foam sample size is .5"x1"x"1 for each.
Foam samples were compressed simultaneously by means of a vise.
Final sample size after one hour of compression is listed in attached document.
Strike Durability: Measured by dropping a standard 4lb flat faced sledge from 10 inches 150 times. Initial foam sample size is the wall thickness of the given commercially available sample for each.
150 strikes was insufficient to do meaningful damage to the cross-linked foams. I grabbed a small cross-section ball-peen hammer and gave them each 40 whacks. Not terribly scientific, but fun. I suppose a ball-peen replicates hitting a thumb or knuckle.
Raw data in document linked above.
Legality: Measured as per commercially available product compared to Amtgard Rules of Play V7.7.
Drill Spot: Meets all legal requirements for Amtgard. Density on par with MC and DuraTube. 33% heavier than AetherTube and 100% heavier than Noodle. This foam is not cross-linked and as such has a very definite life span which is strongly affected by ambient temperatures. Use on a hot day is going to cause the foam cells to burst. Once the foam cells burst, game over. The primary advantage of this foam is the low cost and legality relative to Noodle. The hole size is larger than desired, leading to accelerated breakdown from the inside. The foam comes with a slit in the side which must be sealed and taped carefully or the life will be greatly shortened. The foam must have a tape skin, increasing the overall weight of the weapon.
Noodle: Illegal for use in Amtgard due to noticeably too small diameter (2.4" vs required 2.5") and noticeably too-small foam cushion (.8" vs required 1"). This illegality is the primary reason people in Amtgard have to wear gloves to avoid broken knuckles. In sports which do not allow Noodle the requirement for gloves to avoid broken knuckles is noticeable absent. Noodle is, frankly, a safety hazard which requires players to wear additional safety equipment to avoid being injured. Density is the lowest of all foams measured, beating AetherTubes by 33% and the rest by at least 50%-70%. The primary advantages to this foam are the low cost and high availability during the summer season. However, the large inner hole diameter (nearly 1") and thin walls (about 3/4") mean that the initial cost and availability are offset by the nearly continuos need to rebuild weapons. Noodle also requires a tape skin to last more than a few swings, and will rarely last more than a day as it has large, thin-walled non-crosslinked cells which break with each swing. It's sort of like fighting with bubble wrap, really. Given the cost of Drill Spot foam, I see no reason to allow Noodle on the field in any established group or interkingdom event.
DuraTube: Meets all legal requirements for Amtgard. Density on par with MC and Drill Spot. 33% heavier than AetherTube and 100% heavier than Noodle. This foam is chemically cross-linked and extremely durable. Cell structure is about the same as Drill Spot, but cells will rebound into their intended shape when crushed. As such the cells have an extremely long life span are are largely unaffected by normal fluctuations in heat or altitude. This foam comes ready-to-use and requires no outer tape skin for durability purposes giving it a lower overall weight than Drill Spot. The primary advantage to this foam is durabality and ease of use.
AetherTube: Meets all legal requirements for Amtgard. 33% heavier than Noodle and 33% lighter than MC, Drill Spot, and DuraTube. This foam is chemically cross-linked and highly durable, surpassed only by DuraTube. Cell structure is finer than Drill Spot and the cells will rebound into their intended shape when crushed. As such the cells have an long life span are are largely unaffected by normal fluctuations in heat or altitude. This foam comes ready-to-use but requires an outer tape skin for durability purposes. The primary advantage to this foam is the sweet spot between durabality and weight. It is also easy to use.
MC: Meets all legal requirements for Amtgard. Density on par with DuraTube and Drill Spot. 50% heavier than AetherTube and 120% heavier than Noodle. This foam is chemically cross-linked and reasonably durable but not as durable as either DuraTube or AetherTube as it is primarily manufactured for it's extremely fine and smooth cell structure rather than durability. The cells will rebound when crushed, but the foam has a lower elasticity than other cross-linked materials leading to an overall shorter life than DuraTube or AetherTube. This foam is less affected by heat and altitude than non-cross-linked foams, but don't leave it in your car on a hot day resting on anything as it will deform permanently. This foam comes in sheets and must be constructed into tubes or spiral-wrapped on the core. This building method typically requires several layers of tape or glue and as such increases the weight of the finished product in addition to it's already higher weight. This foam also requires a tape skin for maximum life which further increases the weight. This foam doesn't really have any advantages to it. It's harder to get than the other foams, costs are stil high, material properties aren't as good, weight is higher, and it's harder to use. The fine cell structure is beneficial for working with plastidip or other primarily decorative purposes.
TL;DR: Don't use noodle. MC isn't nearly as good as you think it is. If it was me, I would use Drill Spot if it was a choice between that and MC. If you have the means, order AetherTubes or DuraTubes from WLS. I may have obvious bias, but I also specifically researched the best possible foam to bring to market and then did so.