While there are several features to consider when choosing a remote start the most common decision is how much range you would like. The most basic is the lowest priced and offers a short range which is fine for everyday use say from the window to your driveway. More advanced units cover a greater distance as well as offering confirmation on the keypad for the times you can't see the vehicle(think in a restaurant, Costco office building, school or deep in a parking lot.). A cellular option is also available for those who desire unlimited range. The biggest hurdle that stops some people from going with this option is the monthly or yearly service plan that needs to be purchased.