@willchang409 posted a good document which summarised the...

@willchang409 posted a good document which summarised the options available

CRI, low capex and opex, easy to operate but requires a large area and poor anti-shock load capabilities

SBR - requires less area, high automation, but higher opex and requires higher technical knowledge to operate

MABR - extremely low power usage, anti-shock load capability and no man operation. Relatively higher capex, requires certain amount of operational and maintenance technical knowledge.

So from a pure cost perspective, CRI would be cheapest .. but it doesn't take into account the cost of land and poor anti-shock load capability and from what I have found, it doesn't guarantee class 1a water (happy to be corrected).

MABR is definitely superior to SBR .. for those who can afford the slightly higher capex. Opex its a winner hands down. Also requires less technical knowledge to operate compared to SBR.