I'm not sure he realizes that there are plenty of rock-solid http implementations that power things like web servers and web clients that everyone on the internet uses every day without too many problems. Comparing one http implementation to the handful of transactional engines he's had experience which is anecdotal at best.

It's an apples to oranges comparison anyways, because http is a communications protocol designed to live in an extremely heterogeneous world where you can't control all the variables, as well as be very easy to implement in whatever language/platform you're using.