Commend, recommend, applaud, compliment are comparable when they mean to voice or otherwise manifest to others one's warm approval.
Commend usually implies judicious or restrained praise, but it suggests as its motive a desire to call attention to the merits of a person or a thing.
Recommend adds to commend the implication of offering something that is praised for acceptance, use, or employment by another.
Applaud implies an enthusiastic expression of approval; it usually suggests approval by a large number of persons or by the public.
Compliment stresses either courtesy in the commendation or, sometimes, flattery in the manner or words of praise.