I went with the Issac. The Hans requires a couple inches of space between your head and the seatback, which I don't have in my seating position. The Hans would have forced my head into a downward angle.

Installing the Issac was not difficult, but was not simple either. It's not easy trying to figure out where you install the mounts on your helmet. Try measuring distances on a helmet and you'll see what I mean. You only get one shot at it so you don't want to mess it up. I just eventually gave up trying to measure things, put on my racing gear (all of it - this is key as you will sit up a little higher with your suit on) and the helmet, sat in the car and had somebody mark the spots. My mounts wound up in slightly different places on each side of the helmet due to the way I hold my head apparently, but things seem to be correct.

I don't notice that it's on once I'm on the track, but it can be a pain if you have it on while trying to drive around in the paddock (if you are going straight from your parking space to the track for instance). I find that trying to look at the passenger side mirror takes a little bit of effort to extend the piston a fraction, but you get used to it.

You get the Issac straight from them. Check their website for prices. They are comparable to a Hans.

David