I've only recently discovered LED lighting, and it's great. And I'm now in the process of replacing my low voltage halogen lights with LED (Light Emitting Diode) lights.
And yes, it's true - they're awesome. They're sold as "equivalent", so you don't have to do any figuring out (I like that!) to replace what you have. My old halogens are 20W so I just looked for 20W equivalent. I'm no good at math, but they're as bright as 20 Watt bulbs, and use just a fraction of the electricity.
The problem that I've always had here with the old halogen spotlights is that they got dimmer as they got further out in the yard. I'm also no expert on electricity, but I think it's called "resistance" - the more fixtures I added, the dimmer they got, especially in the Outback. So the areas that needed the light most were the worst.
I bought a 20W equivalent last week just to see if I liked it (and I do!), so I went back and bought a 50W equivalent. The 50W equivalent is for the far corner of the Outback and it absolutely blew me away when I saw it. I got another 50W equivalent for the Outback, but the 20W equivalents are plenty bright, so I'll be staying with those closer in.
Like halogen spotlights, the idea is to uplight the plants. You have to be very careful not to point the lights into anywhere that people will be looking (they're blinding!) so they should be pointed at walls, not windows. And certainly not towards your neighbor's house! Spotlights highlight the plants beautifully, and bounce nice soft light back into the yard.
I pride myself on being current with new technology, so I'm kinda embarrassed that I didn't start doing this sooner. I was afraid that the new spotlights would be terribly expensive, but they're about the same price as the old technology. And no need for bulbs! I see that they're warrantied for five years, and at that time I'll have to replace them if they fail, but I'm thinking that they'll last a lot longer than that. And so will I!