Compared to the other Sony IC recorders I have (ICD-MS515 and
ICD-BP150) the ICD-MX20 is a major let down - especially for the
price.

Although ICD-MX20 is very well-built it just cannot make good
recordings. There are lots of phasing artefacts - even in the
highest-quality mode.

For me the supplied software - Digital Voice Editor 3 - would be
functional enough if it could get along okay with the drivers for my
Edirol FA-101 firewire audio interface. But clicking DVE 3's volume
control seems to disable the Edirol drivers meaning that they have to
be reinstalled. So I have removed DVE 3 from the PC and now use Sony's
WMP plug-in to play .msv files on the computer. Then, for converting
..msv files to other formats, I use NCH SWITCH.

http://www.nch.com.au/switch/

I would recommend you test ICD-MX20 in a store before buying it. There
must be other machines out there that can make better recordings for
the same or far less money.