What is "Melo Chaf Nachas"?
Rav Sadya Gaon: It is a handful of rest.
Rashi: It is acquiring a small amount of property from his exertion.
Ibn Ezra: It is a meager amount of food, with rest.
Rashbam, Metzudas David: It is a handful 1 of money with serenity.
Ri Kara: It is toil needed to finance his household with serenity.
R. Avigdor: It is one who learns a small amount of Halachos 2 , and he regularly reviews them.
Seforno: It is what one attains via intermediate efforts. He attains what is necessary, so he has time for investigation and deeds [of Mitzvos].
What is "Melo Chafnayim Amal u'Re'us Ru'ach"?
Rashi: It is much property acquired via sin.
Ibn Ezra: Much property acquired via exertion is Re'us Ru'ach. He thinks, what will I eat tomorrow? He does not know what the future will bring!
Rashbam: It is a large amount of money with Amal [Metzudas David - and breaking his desire, i.e. something that he does not want to do].
Ri Kara: It is excessive toil in order to find much property.
Rid: It is his Ru'ach's desire, with (due to) envy.
R. Avigdor: It is one who learns much, and he does not regularly review it.
Seforno: Melo Chafnayim Amal is attaining excesses. Re'us Ru'ach is Kishron ha'Ma'aseh due to envy.
Why is "Melo Chaf Nachas" better than "Melo Chafnayim Amal u'Re'us Ru'ach"?
Rav Sadya Gaon: The Kesil says, a handful of rest is better than a double handful 1 of exertion and Re'us Ru'ach.
Rashi: A small amount from his exertion is pleasant to his Maker. Much acquired via sin is Amal (refer to 4:4:1:2 and the note there) and sadness to Hashem.
Ibn Ezra: The Kesil says, a meager amount of food, with rest, is better than a double handful with exertion and Re'us Ru'ach.
Rashbam: The former finances himself honorably; the latter does not.
R. Avigdor: A Mashal for this is, a bird in the trap is better than 100 flying. (The former will remember what he learns; the latter will not.)
Metzudas Tziyon: Chafnayim is two palms clasped together.