Here we have a Mini Split system we installed a few months back which included both a ceiling cassette in one room and a traditional wall mount indoor in another. The two indoor units are both connected to one outdoor unit (pictured at bottom).
This system has not only highly efficient (17+ SEER) but is also extremely quite. The installation requirements are different between the Cassette and the wall mount. The ceiling mount necessitates more time and materials to ensure the cassette is secured and serviceable.
Cassette VS Wall Mount
There are two major differences between the Ceiling cassette and wall mount worth comparing. The first is aesthetic. The second is cost. Performance will be similar between these models although in larger structures/rooms cassettes can have greater benefit for more uniformity in the air due to the ability to flow air in four directions vs one.