Costs
Membrane filtration
Well begun is half done
Smaller quantities of media membrane expensive, Disposables (petridishes, pipettes) expensive
Capital costs of proprietary equipment high
Accuracy
More accurate especially to low levels (less than 100 colonies per 100 ml) Field use
May be operated in the field and in transport if portable incubator used. Transport media can be used prior to incubation
Suspended matter
Not suitable for turbid waters due to membrane clogging
Convenience
Less manipulation and hence lower chance of contamination. Disposable, presterilized equipjent can be purchased
Incubation times
24 h (or oven 7 h in some special cases)