The upcoming travel will be the first time I have used the site to book hotels, with the 5x points being what enticed me.

Airfares are generally the same as what I have seen on the airline website, with one occasion where the fare shown was actually a few dollars LOWER (I attribute that to the occasional mid-day fluctuations I have seen for the route).

I have booked several flights through AmexTravel and never had an issue yet...

The one thing I seem to lose on the hotel booking is the ability to see options like the AAA pricing. Travel in the next month was at a low enough nightly that the 10% isn't that big of a deal though, but it would be a factor on other travels where rooms actually were high enough that 10% across a few weeks is more than a decent dinner.