Personal preference plays a large role in choosing between the two elliptical styles.
Front-drive ellipticals tend to be cheaper and more compact, but having the flywheel in the front can also limit stride length a bit. This can affect taller people whose legs need extra stride room.
Rear-drive ellipticals tend to flatten exercise movements and have a more natural feel. They also tend to be quieter and have fewer moving parts, which can mean less maintenance. These ellipticals may not offer the same range of incline options as a front-drive elliptical, though.