After some more research, I found that Sylvania Silverstar bulbs available in the US are not the same as Osram Silverstar that are not available in the US, but they can be bought online through powerbulbs.com; Philips Vision Plus can be bought at either powerbulbs.com or autolamps-online.com.
The standard H4 bulb for W124 low/high beams consumes 55/60 Watts and produces 1000/1650 lumens. Both Osram Silverstar and Philips Vision Plus H4s consume the same wattages but produce more lumens than standard H4 bulb to justify the plus 50% advertisement, but how much more? Now, if you look at the bottom of the Sylvania web page about Silverstar bulb, you will see that 9003ST bulb, which is the same as H4 bulb, consumes 65/72 Watts but produces only 910/1500 lumens which is less than the standard H4 bulb. Also, note that Sylvania advertises: "Upgrade to the Look of HID".
I had H7 Philips VP on '00 E430 for both high and low headlights (4 bulbs total) and H1 VP on foglamps since April 2001 and still working as of today. I also had H4 VP on Lexus LS400 at about the same time and both bulbs are still Okay. I can see both cars with Philips VP have more light on the road and the headlight looked whiter and brighter than the standard bulb.
I think Osram Silverstars (not Sylvania Silverstar) and Philips Vision Plus consume the same wattages and produce the same amount of lumens, but I do not know which one will last longer. I am ordering 2 pairs H7 Navra Ultra High Output that Daniel Stern at lighting.mbz.org claims can produces up to 2100 lumens but consumes only 65W compares with standard H7 at 1335 lumens and 55W. But it is a little expensive at $60 a pair. I will post comparison result so you can choose the bulbs fit your need in a few days.