I had the original M240 and I now have the M-P 240. The most significant differences between the two are that the M-P 240 has: No Leica red dot logo; sapphire glass (the scratch proof glass Rolex uses for its watch crystals) rear LCD screen (the M240 has Gorilla Glass); and the buffer in the M-P 240 is 2 GB while the buffer in the M240 is 1 GB.

With my M240, the buffer would sometimes get a data logjam when shooting. I would have to turn it off, remove the battery, reinstall the battery and turn it back on. I never had this happen with the M-P 240. that alone is worth the extra $600 cost IMO.

The sapphire glass rear screen is said to cont nearly $1000 on its own, so getting that upgrade plus the 2 GB buffer is quite a good deal for $600.

My M240 was starting to show micro scratches on the Gorilla Glass rear screen - you would not see them unless the light reflected off it at the right angle, but it was annoying. Gorilla Glass is resistant to major scratches, but it would still show these micro scratches.

The more costly sapphire glass on my M-P 240 shows no scratches and I have been shooting with it for 7 years, 2 months.