There have been 133 successful shuttle launches, and 2 failed ones.
There have been 27 successful Falcon launches, and 2 failed ones.
Reentry, not landing.
A design flaw (foam) under launch stress resulted in foam shedding and leading edge wing impacts damaging tiles and ensuring loss of the vehicle on reentry.
I'd argue the failure was in design, triggered during launch, and manifested on reentry. But Columbia was doomed from seconds into flight.
Harder at least as in there are extra steps that can go wrong (re-entry + landing), I suppose it’s debatable which was really a more difficult engineering project…
"The Space Shuttle Endeavour, the orbiter built to replace the Space Shuttle Challenger, cost approximately $1.7 billion." http://www.nasa.gov/centers/kennedy/about/information/shuttl...