In choosing between a two-stroke or a four-stroke, four-stroke engines tend to be better on fuel, quieter, and less emissions. At the time of this writing, four stroke engines are more expensive. Two-stroke engines are generally more powerful than four-stroke engines, thus two-stroke engines are worse on fuel economy, have worse emissions. What they lose in fuel economy and emissions, they make up for in price and more reliability because they have less moving parts.