Rectangular or Column amplifier
There is more than the look of these two different amplifiers that is important. Here although I will call these amplifiers it is really the loudspeaker cabinet that is important.
The simplest amplifier is the rectangular unit. The electronics part being in the same rectangular box as the loudspeaker. Due to the size, these amplifiers will not be extremely powerful. Higher sound levels require a lot of air movement and small devices are physically not able to do this to the same extent as larger units. This is also true for the bass or low frequencies. They do have the advantage that they are generally lighter and more convenient to use.
Looking at the physical shape of the two different units. The rectangular unit usually has one main loudspeaker, and this is true of the Accusound device. The column amplifier has many loudspeakers, the Accusound device has between 6 and 8 main loudspeakers. I say main loudspeakers as often there are one or more smaller loudspeakers in addition to the main speakers to provide a good wide frequency response.
Dictated by physics and acoustics, when multiple loudspeakers are mounted one above the other to produce a column loudspeaker the sound emanating from the column spreads widely in the horizontal plane but spreads much less in the vertical plane. This means that the sound will spread well across your audience and not greatly into the roof or off the floor. This is good particularly if you need to reach a fairly deep audience but is really good to simply cover you full audience with high quality sound.
By the same physics and acoustics, a single loudspeaker mounted in a single rectangular box will emit sound in all directions equally. When you are playing by yourself then this can be an advantage as it produces a single source of the sound, which you can arrange to be close to you and your instrument and spreads it across all your audience.
Making the choice between one and the other is not black and white. A simple rectangular amplifier is great for a single musician playing in a moderate sized venue where intimacy is important, and simplicity is key. A column amplifier will also work in these scenarios but will also be great for larger venues or where multiple musicians are playing particularly if two columns are used to give a wide sound stage. The second column would most likely be one of Accusound’s passive columns, more of passive units later.