As long as the contractor or you are familiar with the quality of the LED lamps, because many lamps on the market are rather costly, but may not be tested for an outdoor application.

If the lamps are proven then the energy savings can be up to 80% with a lamp life of 6-8 years as opposed to many quartz halogen bulbs being 6-8 months.

Another issue to address is the temperature (degrees Kelvin) of the light or color. Typical quartz halogen is somewhere in in the 3,000-3,200 degrees Kelvin or warm light, but LED lamps can be also purchase in 4,500 -6,000 K white to blue tones respectively.

Another consideration is the wattage of the lamps can be inconsistent since the lumen (light output) to watt ratio varies greatly between lamp manufactures. If you are not careful the amount of light produced from the new LED is not as bright as the previous incandescent. Most people are not happy with paying considerably more, but getting less light.

I hope this helps.