I have a Speed Stir and while I would say it is convenient, it is not a must-have IMHO. My advice to someone new to the TFP method is to spend their money first and foremost on a good test kit (like the TF-100) - that's a must-have item. Proper use of a good test kit will save you $ over time by helping you to avoid problems before they start. If you can swing the Speed Stir along with the test kit, then go for it. About the only annoying feature of the Speed Stir is the auto shutoff after about a minute. When this happens, I'm usually about 3/4 of the way through the CH test and the CH test is where the Speed Stir would be most convenient if it weren't for the auto shutoff. I then have to stop adding reagent, remember how many drops I added, and restart the unit. My pool's CH level is around 350 ppm. If it were considerably higher than that, the auto shutoff would be even more annoying since it would happen an additional one or two more times before I completed the test. I would prefer that the Speed Stir continues to run until I shut it off or at least have the ability to manually override the auto-shutoff.