Build a sentiment classifier for product reviews

Sentiment classifier for short (1-2 sentence) general e-commerce product reviews. Positive = clearly favorable/satisfied, Negative = clearly unfavorable/disappointed, Neutral = factual statements, mixed sentiment, or lukewarm reactions. Edge cases: 'works as expected' is Neutral, 'not bad/it's okay' is Neutral, mixed pros/cons like 'good quality but expensive' is Neutral, 'could be better' is Negative.