I got my Vinmetrica SC-300 a few months ago and have been very pleased. It simplifies and greatly improves the accuracy of my testing and for me is a valuable piece of equipment to have. The online videos are excellent and the web site gives an instruction summary "cheat sheet" for each test. I did not buy the magnetic stirring bar, electrode holder, or burette.
It's easy for those who have bought it to say others should too. However, it may or may not be for everyone. I make mostly kits and to be honest most kit winemakers do not need that level of testing to do well. Kits have been balanced for pH and acidity and the SO2 addition instruction guidelines (1/4 tsp K-Meta every 3-4 months per 6 gal.) should cover you well. (But you really don't know until you test it!)
I began ordering juice buckets and realized that the pH test strips and other simple testing methods had their limitations and did not seem accurate enough for me. Since I had not yet incurred the expense of a pH meter, the Vinmetrica was especially good for me because it measures pH, TA, and FSO2. I like knowing I am getting more accuracy in my testing and can use these test results to adjust pH or acidity of must in my juice buckets if I need to.
Now I know in each batch exactly how much free SO2 I have and can begin to equate that to K-Meta I have added for my wine kits. I also test some commercial wine now and then to get a feel for the numbers.
In assessing your wines at various stages of their development, the numbers are really important, but remember: so is your taste!
NS