Crimped or pressed connections use special copper fittings which are permanently attached to rigid copper tubing with a powered crimper.  The special fittings, manufactured with sealant already inside, slide over the tubing to be connected.  Thousands of pounds-force per square inch of pressure are used to deform the fitting and compress the sealant against the inner copper tubing, creating a watertight seal.  Advantages of this method are:
*A correctly crimped connection should last as long as the tubing.
*It takes less time to complete than other methods.
*It is cleaner in both appearance and the materials used to make the connection.
*No open flame is used during the connection process.
Disadvantages are: 
*The fittings used are harder to find and cost significantly more than sweat type fittings.
*The fittings are not re-usable. If a design change is required or if a joint is found to be defective or improperly crimped, the already installed fittings must be cut out and discarded. In addition, the cutting required to remove the fitting often will leave insufficient tubing to install the new fitting, So couplers and additional tubing will need to be installed on either side of the replacement fitting. Whereas with a soldered fitting, a defective joint can just be re-soldered, or heated and turned if a minor change is required, or heated and removed without requiring any of the tubing to be cut away. This also allows more expensive fittings like valves to be re-used if they are otherwise in good to new condition, something not possible if the fitting is crimped on.
*The cost of the tooling is very expensive. , a basic toolkit required to sweat solder all the copper pipes of a typical single family residence, including fuel and solder, can be purchased for approximately $200. By contrast, the minimum cost of a basic powered crimping tool starts at around $1800, and can be as high as $4000 for the better brands with a complete set of crimping dies.