Any real life experience?
You can make an arduino/avr consume more current than a msp430 and you can make a msp430 consume more current than an arduino/avr: current consumption is more software dependent than hardware dependent, regardless of how chip vendors tell you otherwise.
What's truly unique about msp430 is its ability to start its crystal oscillator almost instantly. No one has been able to do that.
Otherwise, quite a few chips have come close to msp430 or beat it in terms of current consumption/Mhz.