Agreed @FuLL_Met4L. rather pay extra for better performance. I know Samsung makes the best SSD's on the market. That EVO 850 also has a 5 year warranty! Which is really nice.
You'd also do well to look at the Crucial BX100 series. If you're looking for a great value / performance SSD, from my research I understand that it's neck and neck between the Samsung EVO 850 and the Crucial BX100 product lines!
At the same price the Samsung 850 EVO's are better no doubt. The Crucial BX100's have had some fairly good pricing and are pretty damn close to as good as the Samsung's. The 250GB BX100 is often priced VERY competitively on sale.
I know Takealot and Wootware are both selling the 850 EVO 120GB on sale at the moment. I'd buy from Takealot in this case as shipping will be free.