i havent used smartchlor but i looked into it because I'm a huge fan of automation. unfortunately it doesn't get the cost/benefit ratio right for me. It's significantly more expensive than just doing it yourself.
i use a method which has been working really well. I use a modified version of the dichlor/bleach method, starting with dichlor and switching to bleach after enough CYA has built up. But i've setup the bleach to automatically dose the tub at regular intervals.
I use a two part doser (
https://www.bulkreefsupply.com/brs-2-part-doser-1-1-ml-per-minute.html) feeding from a 3 gallon tub of bleach. to control the dosing I bought a smart plug and use an app on my phone to set a schedule which will automatically dose the tub at regular intervals.
It took some initial tinkering and trial and error to get the schedule right, but now that I've figured it out it's cheap, I don't have to worry about CYA build up, and it just plain works. I've been using it for almost a year and i always open up the cover to perfectly clear don't even need to think about it. I'd highly suggest this method to anyone looking to automate and simplify their maintenance.