If I use HD Monitor Pro it records to QuickTime. So if I deliver this to a client and they are editing off of MXF files does this mean they would have to convert back to MXF files thereby suffering some quality loss in the process?
They are just different container formats, if the software you use allows you to output to MXF and is reasonably intelligent, it won't re-encode anything and just put the same DVCProHD frames into the new container format.