In terms of brightness, HID's and LED's are quite similar. They'll almost always be brighter than halogens.
LED's are pretty much all around better than HID.
* They're easier to install since there's no ballast that needs to be mounted.
* They use less power.
* They do not need to warm up (HID's take a few minutes to get to full brightness).
* They're more durable (No sensitive glass housing).
* They can be safely flashed (HID's are sensitive to flashing, doing so will reduce lifespan)
The only thing that HID's have going for them is that they're cheaper and proven. Where as many LED's are dying early due to poor designs (Mostly to do with thermals). This may have changed since I last shopped for them (2 years ago), but it's important to keep that in mind when looking for them.
LED's are pretty much all around better than HID.
* They're easier to install since there's no ballast that needs to be mounted.
* They use less power.
* They do not need to warm up (HID's take a few minutes to get to full brightness).
* They're more durable (No sensitive glass housing).
* They can be safely flashed (HID's are sensitive to flashing, doing so will reduce lifespan)
The only thing that HID's have going for them is that they're cheaper and proven. Where as many LED's are dying early due to poor designs (Mostly to do with thermals). This may have changed since I last shopped for them (2 years ago), but it's important to keep that in mind when looking for them.