I would say, it makes a difference like any other bike. Each gear is translated to a ratio called Gear Inch http://www.sheldonbrown.com/gears/ an for the same gear inch you get about the same affect regardless of the wheel size. Having multiple GI's (one per 'speed') makes it easier to adjust do varying conditions (speed, slope, etc).

Personally I prefer to have at least few gears. In general, the stronger rider you are, the less you need gears.

Hope that this answers your question.

Edit: you may want to take a look at this local company. They have decent high value bikes.

http://www.citizenbike.com/catalog.a..._category_id=1