Welcome to TFP! Hands-down I'd say the TF-100. Great value, fast shipping (even with the pandemic) and very good supply of reagents. The next option is the Taylor K-2006C. I got the TF-100 several years back and never looked back. See Test Kits Compared. If you can, also consider the magnetic speedstir for efficient mixing like a pro. Really helps a lot. Have a nice weekend.
^^^^What he said^^^^. The TF-100 is the best value for the homeowner with a pool. I love my Speedstir. Buying both gets you into free shipping territory. If you have a salt water pool, you'll need the Taylor K-1766 as well.