Is the Merlin engine the workhorse of future spaceflight?

The engine looks good to Stewart Money at Space Review.

“Those Merlin engines are fantastic,” offers Tony Stark to Elon Musk in a cameo for the summer movie Iron Man 2. The brief exchange, occurring as it does in the Monte Carlo Hotel de Paris prior to the Monaco Grand Prix, invites the space enthusiast in all of us to draw an analogy between the two industrialists—and for those inclined to stretch a cameo further than anyone should, between the aforementioned Merlin engines and the Formula 1 racers about to take to the track.