The darkroom automation meter, says it works as a densiometer, but is it from an enlarger or directly from the negative?
It is what is called an 'easel densitometer'. It measures the density a negative produces when it is projected by your enlarger. Obviously, if you are doing contacting then this isn't the right densitometer for you. If you are enlarging, though, an easel densitometer produces better measurements. Two negatives can read the same density in a bench densitometer but produce different densities when enlarged because one is a thick emulsion film and the other a thin emulsion and have different callier coefficients or because flare from clear shadows areas is reducing highlight density.
Another real advantage to an easel densitometer is the size of the measuring spot. Because a bench densitometer works at 1:1 it can't measure highlights or small shadow details on small negatives (and many big negatives). An easel densitometer works at the print size and so can measure small highlight and shadow details about 2mm in size.
A color densitometer won't be of much help printing, they are designed for graphic arts applications and for quality control in color labs. A color analyzer will produce density measurements on the easel. The effective density for a color negative will change with different papers. Color analyzers have provisions for paper calibration - some with plug in modules for each paper you are using.
If you are doing Zone-system type film testing then either an easel or bench densitometer can be used. However, realize that the purpose of zone system testing is to match the film to the paper - the magic 0.1 over B+F isn't a number carved in stone but one found to produce good prints on the paper the folks who came up with the number were using. If you are using a different paper you may find you get the best prints with a speed point at 0.2 OD. Because the end-point of Zone system is the print, measuring the effective density your negative produces in your equipment is the real number you are looking for. Once you have your system calibrated for one film it is easy to find the exposure and development parameters that give you the same print densities for another film and process.
If your interest is scientific, and not aimed at producing prints, then a bench densitometer may be a better choice.