SpaceX has made a tremendous achievement in recovering 11 first stages so far, and recovering one after re-use. However, the re-use of the Dragon capsule during the CRS-11 mission was over-stated. What was re-used was the pressure vessel. This means that the craft from the CRS-4 mission was stripped down to its hull and then rebuilt. It’s essentially a new spacecraft built upon an old shell.
SpaceX is not able to re-use the capsule after it lands in salt water without this complete rebuild. Someday they may be able to achieve full reuse, when they can land the capsule on solid ground.
Update: At the ISS R&D conference, Elon Musk stated that the first capsule re-use cost as much as, or more than, a new Dragon capsule. Water intrusion was listed as one of the causes. All of this confirms what I previously stated. However, SpaceX has expressed that they may be able to prevent water intrusion in later flights, leading to a capsule that is more readily reusable.
At the same conference, Musk announced that non-parachute landings for Dragon 2 were being abandoned, so apparently there will be no ground landings. Apparently the original propelled landing design used legs protruding from the heat shield, and these were deemed unworkable.