Also remember 36x20 is an odd footprint, 36 x 18 is a common/standard foot print when looking for a stand to use, it may be hard to find a 36 x 20 stand w/o going custom.
I would pick the ADA 90-P, in the US, it is the same price as the Do!aqua 90-P, not sure if the same is true for Canada.
Since you are buying a large tank, might as well get the best option and do it right the first time. quality/reliability are the deciding factors.
i did look at the ADA 90x45x45 cm, it's more expensive than the Blau Aquaristic 36x20x20 inch.
ADA 564,00 $ 166 L
Do Aqua 369,00 $ 166 L
Blau 479,95 $ 230 L
as you said, i want a pretty solid set up for that tank, i'm looking for a nice design/nice looking build (for the ligntning) and a good quality.
i will avoid paying a ADA or Blau and put cheap stuff around it.