I'm a newb, so don't trust what say as if I know what I'm talking about, but I used Klasse AIO on the glass with the pc, then hand applied the SG, and it appears to work better than a fresh application of rain-x, and I can only assume that it will last longer. The bug splatters rinse off very easily, but they do leave a VERY slight ghosting that I take care of with a thinned down application of the SG from a spray bottle.
Before the AIO, I polished the glass with a cutting pad and Meg's scratch-x, and it worked great, though I probably did not need to get that aggressive. I had some water spots I wanted to remove.