It may require a top-level comment, and I actually got mine 4 years ago, but I'll also plug Sparkel which is the "can-less" carbonator: https://sparkel.com/products/sparkel-beverage-system ($150 for the system). It is unquestionably slower than actual CO2 bottles (a "level 3" strength carbonation takes 2 minutes), but for me it more than makes up for the bazillions of minutes I don't have to spend driving to the store to exchange CO2 bottles. Your mileage may literally vary :)

This being HN one can also "void the warranty" by just making the recharge packets yourself with 10ml of baking soda and 10ml of citric acid, both of which one can get in multi-pound containers for ease of assembly. I use something akin to this[1] to keep moisture out of the charge until I need them, and I make them in batches of 30 which takes me 7 minutes for all 30, using any 10ml sized scoops[2]

1: https://www.amazon.com/Goeielewe-Graduated-Transparent-Measu... but with the advantage that I got mine at the $1 store

2: e.g. https://www.amazon.com/GSHLLO-Stainless-Measuring-Ingredient...