Should you change your Landscape Lighting System to LEDs? Definitely!
Here is the breakdown for the typical costs associated with having your Outdoor Lighting System with LEDs vs Halogens. Though the costs are a projection and not 100% accurate, it is a noticeable difference in energy consumption.
Halogens produce significant heat - if you grabbed one after it has been on for a while you would know. They also "burn out" quicker than LEDs - way quicker and you are basically replacing them every 1.5 years or so. That said, they are also cheaper to replace.
The thing I love about LEDs is their reliability. They last, and if they don't, they are usually under warranty. At Apex Outdoor Systems - we only install LEDs (and the upgraded Integrated Fixture) because they are so reliable and customizable.