This study compares the effectiveness of five leading grammar/style analysis software packages in analyzing business students' writing. The software exhibited considerable differences in the following areas: correctly identifying various mechanical and style errors, avoiding annoying and misleading false error messages, and providing helpful remedial advice. No prior research study has empirically compared grammar/style analysis software along all these important dimensions. PowerEdit was found to be the overall superior package, demonsrating proficiency in detecting errors in punctuation, sentence structure, passive voice, and weak wording. The results have significant implications for utilizing grammar/style analysis software to improve students' writing.