Bandoneons are basically divided in 2 categories: the unisonoric models (inappropriately called chromatic) and the bisonoric (inappropriately called diatonic), with several different versions within each category also. For example, in unisonoric versions you find at least 3 different layouts: Peguri (originally spread in France and Belgium and now in all Europe), Kusserow (very rare, with small diffusion in Europe) and Standardbandonion (invented by bandonion virtuoso Heinz Schlegel, and largely unknown), but the list goes on.
If you want to play bandonion and you are in search for an instrument, probably you will read in some blogs or forums that the only way to get THAT sound is to buy a 142 bisonoric instrument, and no other versions of the bandonion's layout can provide you such a colourful sound.
Well, right this summer I attended a music stage with french bandoneon master Olivier Manoury. He plays chromatic bandonion, and hearing him I realized that a chromatic bandonion sounds great exactly as a diatonic one, when you are good enough to play bandonion.
So, do not give too much attention to those who say you have to buy a 142 Rheinische bandoneon OR you will not have that sound and you will never play real tango or real bandonion. Everyone feathers one's own nest. Chromatic bandoneon sounds great exactly as any other 142 bandoneon, if you are able enough to handle it giving expression with bellows and weight pressure. You should decide with which layout playing according to instrument availability, budget, experience and your personal attitude.
And what about 144 bandonions?
Generally these instruments were built for German Folk music, and thanks to a third reeds row they are tuned with "vibrato". But you can silence the third row and tune the remaining 2 reeds at perfect octave, et voilĂ you have a 142 bandoneon sound like.
Bandoneon is a nice instrument because in a small "box" you have an unexpected extension: in the 33/38 Rheinische Tonlage the left side (bass side) starts from C2 and reaches up B4 (3 octaves), while the right side ("singing" side) starts from A3 to B6 (3 octaves again).
The 2 sides extensions partially overlap, for a total extension of almost 5 octaves. Not bad for a little squeeze box!
Let's see a comparison with some musical instruments in the next infographics:
The range of 144 is slightly less than 142 model, but the total extension is sacrificed in favor of a more coherent keyboard, in fact chromatically complete for both opening and closing.