Interesting that the IM has 3/4" glass, but CDA only has 1/2", RSR is in between at 5/8 or so.
RSR adds a lot more parts in the sump, so is not a 1-1 comparison on price.
Note that 3 sides = 3 sides to keep clean.
IM seems like a great deal. Lower price, thicker glass, better low height...