I'll answer for Trey since I asked him the exact same thing when I saw it at a dyno day. He said that it had been fine, though a bit slow to crank in the winter, it had never not started the car. (Trey feel free to correct if Im wrong.)

I will prob get one when my stock battery takes the dirtnap. Keep in mind however you will likely have to rig something with your battery holder to keep the (much) smaller battery in.