Hi Folks,
The dependent criteria for depth penetration are, the type optic used, ie angle spread, manufacturer make and material grade used, but more importantly what wattage of LED you are using and how they are driven. An LED unit using 0.25w/0.5 watt LEDs will not penetrate anywhere near a 3w/10w LED for depth no matter what optic is used.
This is where you need to be comparing apples with apples. You cannot compare a 1w/350ma LED with a 0.25W/350maLED as it has roughly triple/quadruple the power factor.(Depending on losses) There is also a certain point where increasing the current will not improve the lighting level produced.
NB This is not a comparison of the above lights mentioned above in my example, but a guidance to the specification comparison criteria.
Most light units have low powered LEDs to keep the price low in manufacture. However the higher wattage ones have more heat dissipation issues, so you need to ensure that you have good heat sinks.
There is a lot of good information available on the web if you look under LED manufacturers ie OSRAM/CREE/LUXBRIDGE etcetc.