I started out renting an Elise from But.Box, which I eventually purchased. This was followed by the Peacock two years later. While the Peacock was certainly an improvement, it has not been an easy road. I live in New England in an older home that does not have good environmental control inside. Therefore, when it is dry outside, it is dry inside, and when it is humid outside, it is humid inside. Now the Peacock. The sound board is one solid piece of choice wood ideal for the purpose for which it is used, except that this piece of wood is quite sensitive to humidity changes. At the beginning of this winter, when things began to really dry out, the sound board responded by changing it's shape and allowing air to pass other notes, causing multiple notes to play, as well as other tonal changes - to the point where the instrument became unplayable. I contacted Wim, who immediatly diagnosed the problem, and I sent the instrument back to him which he corrected and then sent it back me; with instructions that I had to control the humidity carefully. To this end, when the instrument is not in use, it is kept in an enclosed air tight container with a satruated Calcium carbonate salt solution in a remote part of the chamber resulting in a relative humidity that is maintained in the low 40s%. This has worked very well. When I do take it out to play, which I do daily, if it is VERY dry out, the instrument will handle this for close to an hour until tonal changes again begin to occur, at which point I must put it back into the chamber and "let it rest". I know that other concertinas (such as the Baumount) will use a plywood for a sound board, which is less succeptable to humidity changes. So, when choosing which instrument to use, consider the environmental conditions that the instrument will be subject to. If you live in fairly stable environmental conditions, a traditional sound board may be best. If you live in an environment with wildly fluctuating envonmental conditions, perhaps a sound board made of quality plywood would be best.
Finally, the left side of the Peacock would often drown out the right side. So to fix this I placed into the concertina a baffle on the left side that has proved extremely effective.
With the two above issues addressed, the Peacock has been an instrument that I now enjoy playing; but it has been a learning curve for me on how to care for and work with a musical instrument. I have never played the Baumount, but perhaps the above would help in figuring out what to choose.