AIWB isn't uncomfortable at all. I've driven for hours carrying AIWB and haven't had problems. Take a look at the Bladetech Nano holster.
I've tried a number of AIWB holsters and I prefer the N82 above any others I've tried.
Not comfortable at all and I don't like aiming directly at either the family jewels or a main artery.
First and foremost, appendix carry mandates absolute attention to the safety aspects of gun handling. That being said, appendix carry can be very useful. I have carried in the appendix position, both IWB and OWB, for years, though my "primary" remains at 0300.
I have used three different soft-side IWB rigs at the appendix position to carry various revolvers, but as they are no longer available, they are irrelevant to this discussion. I frequently use a Kramer Crossdraw to carry an SP101 at the appendix position, OWB, while another weapons is carried at 0300. I should note that even though this holster is termed "Crossdraw," I do not wear it in crossdraw fashion.
As I thought I was about to buy a G26 recently, I acquired a pre-owned but as-new Desbiens AIWB rig. The Glock purchase has been delayed, however, so I have not actually used this holster.