Love the SIS products and they are rocket fuel in a pouch! Usually don't have issues opening but this batch seems to not be easy at all....even trying to use the teeth to rip open the packet is VERY hard. That is the only reason it didn't get a 5 star is due to the access or ease of ability of opening the product.
I've been using the GO gels on longer rides and during my last (well, only) race of the year so far.
The down size is that they take up more space than a regular gel; however I find that they go down so much easier--no interminable aftertaste or need to gulp down water like other gels. My stomach seems to tolerate them better as well.
I've tried the vanilla flavor and tropical flavor so far, with vanilla being much better.