In terms of light out-put,how do solar landscape lights compare to low voltage lights?

I have been looking at Malibu Solar landscape lights and notice that they post no information as to how much light they put out. They have some solar lights that have two LEDs and some with three LEDs. How do these compare with the standard 4 watt low voltage lights?

About the same but more importantly for solar non-wired lights, what is the average run time? Some cheap ones will last only 4 hours while others can make it all night.