Okay, from what i see in this post, there are four divisions of how you can rate bulbs:
by price, color, by brightness (lumens), and by effectiveness. i'm just going by what i see posted on the manufacturer sites. as reference, i assumed stock to be the sylvania standard 9006 halogens. although i know they aren't.
price: check your wallet.
stock: free
silverstars: ranging from $25 to $50 depending where and if you have the $10 rebate
Piaa: about $70+
Other Brands: $15+
HIDs: $230+
color: any aftermarket bulb will give you color. take your pick. it doesn't matter if you like green, blue, white, or pink, it's out there.
Stock: 3140k yellow
Silverstars: 4000k white
Piaas: 4000k (xtreme whtie) 3800k (platinum super white)
Other brands: whatever they claim its near. usually 4300k or bluish.
HIDs: whatever it's labeled as. (4300k(sunlight)-15000k(ultraviolet or whatever is up there))
*all assuming they're all mildly accurate
for reference, a color table...
Yellow:
1500 k Candlelight
2700-2900 k Yellow painted fog halogen bulbs
-------------------------------
Yellowish white:
3200 k Sunrise/sunset
3200 k Premium H7 non painted halogen bulb
3400 k 1 hour from dusk/dawn
-------------------------------
White:
4100 k Philips/Osram OEM HID D2S
5500 k Bright sunny daylight around noon
----------------
Blueish white
5500-5600 k Electronic photo flash
6000 k Philips Ultinon HID D2S
6500-7500 k Overcast sky
-----------------
Blue:
9000-12000 k Blue sky
-----------------
Purple:
28000 Northern sky
12000-30000 k Ultra Violet light (black light)
---------------------------------
brightness: okay the silverstars are brighter than the crappy superduperxenonhalogen knockoff bulbs in the long run (after the bulbs start to die down with prolonged use). HIDs produce more lumens, regardless.
stock: 1000 lm
silverstars: 1000lm
piaas: claims a 1870 lm.
knockoffs: varies. usually claims a 1870 lm. rarely gets there or stays there over a few weeks.
HIDs: 5200k~3200lm, 6000k~3000lm, 7000k~2800lm, 7500k~2400lm
effectiveness: how well your eye responds to the light. the human eye responds to the light scheme of natural sunlight best. in bad weather, yellower is better.
stock: best all around
silverstars: near-stock. better for standard nights.
piaas: pretty good
knockoffs: crap
HIDs: pretty good due to high intensity (lumens), not color.
besides, the actual measured silverstars vs. standard halogen, you paid $40 or so to get a whiter light, not any stronger, resulting in a slightly better result for standard weather at night.