What if you had a way to only test the UI in isolation (without actually sending messages) and only test the message sending functionality (in isolation) without having to deal with UI. Well, this is where Model-View separation comes in handy. Talking to your model without going through the UI is a lot more robust, fast and targeted (it's a method call, not combination of UI interractions AND function call) — you can easily test for a lot of different scenarios that have nothing to do with UI but are potentially bug-prone on the backend. So clearly – a win, if you can pull that off.
Before placing an order, you might want to know what it will cost to go this route. Typical prices for concentrate are $8 to $14 per quart, $7 to $10 for pints, and $3 to $4 for 4-ounce bottles. Shipping will be expensive—count on an additional 30% to 70%, depending on how much you order and the distance. Depending on these factors, flavoring costs are likely to range from $ to $ per liter. Obviously, at the high end you won't be saving much if any money over SodaStream's flavors, once you add in the cost of sweetener; but if you can buy a few pints or quarts at a time, the total cost (concentrate plus sweetener) will fall in the $-$ range. Most or all of the ingredients will also travel less than the SodaStream bottles, and what does travel will mass less, which all adds up to being better for the environment.