I have an old ElectriCalc Plus which is probably the fore runner of the Pro model. It was given to me by one of the contractors I deal with.
I use it mostly for voltage drop calculations where I can do many what if ? scenarios in a very short time.
One drawback of my model is if you are figuring several size conductors in a raceway, the calculation is based on all conductors being the same size as the largest.
It is handy, but to this day, I'm not sure that I would be willing to buy one. Everything the calculator does, so does a spreadsheet in my computer. If you do a lot of calculations in the field, then this would definitely be a must have tool.
Few things are harder to put up with than the annoyance of a good example.
It took some time to learn how to use it. Still some features I don't know or use. Because it has a limited screen and key pad many things are abreveated. It can be easy to have it set to the wrong phase or temp setting. The defult is what was used last. No trouble once you remember to check it.
I disagree with Tom on the raceway sizing. At least with my model. That is a great feature to be able to add up all different wire sizes to get a conduit size.
I just checked to make sure with an example: 1 #000 Thhn 9 #14 Thnn 3 #12 thn
Of coarse it only tell you the code minimum conduit size.
It is programed with a small module that has a version of the NEC. I looked for one that had the 99 version module on the net plus a mail in credit for the 2002 nec module. Otherwise the one at a store only had the 02 nec.
It is also nice if you are not sure of how to do the math on the job. It is easier then looking up in tables.
I use it for adding up the bills. Had the same battery for maybe a few years.
It is so quick: 700 w, 120v, 260' length run, 75 deg C, 1 PH answer - 5.8333333 a, #8 thhn, #8 EG, VD 2.4 v, VD 2%. If the load was an inductive motor it would be .33HP Without entering the length it will tell you to use #14 Thhn up to 88.532573' run It will tell you some OC sizes
Above answers figured in 30 seconds. Takes longer to write down answers.