Not sure what the Smart Stir is, but the Speed Stir works great!
I got the regular kit, and as mentioned, you'll be doing a lot of testing just to learn the ropes. I know I'll be refilling one of my Reagents soon as well as my CYA solution.
This is a Great place to learn for sure!
My kit lasted 4 years, then I had to replace a few things. My pool was so easy to take care of, once I got everything right at the beginning of the season and figured out the proper setting for the SWG I rarely ever had to do anything. Maybe I was lucky, I ran my robot and once in a while would add water. I used the cheap strips and used the kit like once a month, the strips were pretty darn accurate.