This analyzer is fairly basic in that it can only take integrated readings and not spot readings. Therefore it could be used to read a gray card image or other images with a diffuser that comes with it, but not a specific spot in the image.
I used one briefly years ago and it seemed accurate enough for its intended use. But like most analyzers you must program and analyze the same film type for accuracy. If you program with one type of film and analyze another, the spectral characteristics of the different film dyes will throw off the readings and results are unpredictable. This is a basic, but not well known limitation of color analyzers.
I have a Lici (OEM manufacturer of Jobo brand) Colorstar, and have used less sophisticated analysers in the past.
The best tool for printing and learing colour is the colour print viewing filters by Kodak
The colour ring poster around found in many 80's era Kodak Dataguides is also useful.
The analyser helps to establish your base filtration, and exposure time.
I find my Lici is good, because I print RA-4 probably only 6-8 times a year, and it quickly gets me within range for the first test print.
I think if I printed RA-4 more often I would use the analyser less often.
Yes, I concur with RPC that film bases colur casts do vary. Fuji's Reala has a base that is very different from what I was used to. Tungsten balanced films from Kodak also had different coloured bases from the usual range.
I have used it more then 10 years ago. It can do indeed integrated readings only and for each color seperated Y/M/C.
I am using a Fem-Kunze CFL-4012 now. Spot and integration and all corrections in one measurement.
A big difference and much more acurate.
I have one and find it very helpful. You have to calibrate it on the "perfect print" but once done then it gets you a reasonably balanced print on almost all occasions. Most landscape or outdoor scenes are fine as are any that have a range of colours.
If there is a predominance of one colour then the balance will be off but that will only cost a couple of extra pieces of paper to get right especially if aided by a set of viewing filters for correction.
As Mike has said, if RA4 printing is only an occasional thing then the analyser is quicker and easier than trying to get there by trial and error alone.
Can't speak for the U.S. but in the U.K. this analyser is quite cheap and good value for money IMO