The Soundsmith MK ii models with the DEMS alumina mounting rods and a non-"boxy" body are supposed the have lower internal resonances.If you have a tonearm with does not permit azimuth adjustment, using the middle alumina rod allows some adjustment and would be an advantage.When I bought my Aida, I chose the older model at a big discount because my Graham 2.2 had an elastomer pad under the cartridge mount and is fully adjustable for azimuth. I don't know if the new body contributes to lesser resonances, but I preferrred the looks of the older model, and certainly the price. I do not believe the moving parts of the models are different.