One main feature everyone ignores is, how good is the phone itself. After all, they are phones and the features of them are truly secondary to the entire package. I've read/heard about the S4 not doing as well in the voice communications department such as, dropping calls, poor or below average call quality in comparison to the razr max hd. Also, for those wondering, I hear the same about the i5 phone compared to the razr max hd, not so good or drops calls more often.
All the features on the Samsung S4 that are a winner over the Razr Max HD are: 1.9 quad core cpu, larger screen, removable and replaceable battery, better camera front and rear, weight is less and a few other things totally unrelated to telephone/voice matters.
Razr MAX HD advantages: Double the battery life when new, better voice call quality and connectivity, more ruggedly built and that's about it. It has a dual core 1.5 cpu.
For those looking for a cell phone that places and receives calls better and has excellent battery life (when new) the Motorola is the winner. How well those battery's last no one has reported so, maybe after 2 years, the Razr Max HD might have to be replaced since the battery is not replaceable. This is the most ridiculous design of all, expecting folks to throw out a $500 phone to replace a $20 battery which could fail on month 2 or just after the warranty ends.