I'm quite a fan of Mike Ray's books on flying airliners. In his earlier books he has clearly indicated that MSFS is the way to go for airliner simulations and not X-Plane. In his more recent books, however, he hasn't mentioned X-Plane either negatively or positively at all.
I hope this upcoming IXEG will change his mind because I would love to use an updated version of his handbooks based on the X-Plane platform. Of course, if IXEG would work together with Mike and release the Aircraft together with a dedicated book written by Mike, that would be absolutely brilliant.
There is the usual impatience that is common to flightsim hobbyists when a really promising add-on is soon to be released, but I must admit that while I would love to see an early release, deep down I prefer the IXEG philosophy of getting this done properly the first time. From what I have seen and read, it looks like this will be a superb piece of software engineering.