Palestinians should boycott SodaStream and related products because it is their right, and the company stands against their fight for freedom. This almost creates an obligation to boycott. Boycotting SodaStream sends a message to the corporation that SodaStream must answer to all people when they take a stand on one side of the debate.
If you do boycott these problems, there will not be enough supporters who buy these things to make even a small dent in these big companies. The soda stream company makes there money mostly on the soda making machine, which most people will have to only buy one of anyway.
Soda Stream gives jobs to Palestinians and Israelis alike. It provides much needed income for some and there is no reason to boycott it. It is a company, not a government. If every company in that area is boycotted then there will be no place for people to work, shop, etc. Palestinians will be hurt as well as Israelis.
There's no reason to boycott SodaStream. They're not exploiting anyone, the jobs are well paid by local standards, and they include generous benefits. The silly boycott is really just the usual cast of anti-Semites who would do or say anything as long as it means they get to openly hate Jewish people.
Since the record reflects that International Law defines the Israeli settlements on the West Bank as being illegal the fact that SodaStream products are made in facilities located in West Bank settlements is a violation of the Fourth Geneva Convention, (which specifically prohibit an occupying power (Israel) from profiting from land it occupies. The SodaStream plant pays substandard wages and has lower safety rules than plants located in Israel.
SodaStream should be boycotted until it removes its illegal plant from the West Bank.