Based on my experience, this product was a waste of money. The syringe was difficult to use, and the solder didn't flow smoothly. The tip was too big for precision work, and the application was messy.
Works great even in my reflow oven. Good for about a year or so if you keep it in the fridge between uses and let it come to room temperature for about 3-4 hours before using.
Did surface soldering and it was great. The only problem was that I needed very little. The rest is in my fridge and will most likely be thrown away. I just don't want a full tube of this stuff. But for what I did, it worked great.