Take a look at the links I provided.

The Newbeam is a great conversion but is a lower output model. It has 3x5mm LEDs. It is basically the "reference" of all conversion kits. I find the 3x5mm LEDs provide a very useful, flood of light. It also plugs in the same location as the bulb, so function is the same as normal.

There are a few "camps" of the higher output conversion kits. Personally I've liked the ones Dat2Zip (Waye) produces. He has a variety of modules based on what characteristics you want (brightness vs runtime). However, based on the number of choices and how these install, you need to understand the tradeoffs better than with the Newbeam.

-john