I am looking for a 100 watt, medium base HPS lamp for one of my fixtures. I am biased towards the GE, Philips, or Sylvania types. Of these and all the other brands, which is the best in terms of light quality, durability, and average life? Also I thought there were color improved HPS lamps to operate on standard HPS ballasts, but I cannot find any. Any suggestions?

IMHO I would say go with GE. I have had the best expirence with them. For the Philips if you can find a NOS Ceramalux w/o the Alto feature you would be just as good as with a GE. The Altos are junk IMO. I dont have any expirence w/ sylvania so I cant say!

I think probably the best HPS bulb you could come up with would be to find a USA-made Lucalox.  I have a spare one of those for my yard light for when the pre-Alto Ceramalux burns out.

Ok thanks for the input, that's pretty much what I thought. I have always had good luck with GE and Philips lamps but I think the only Philips lamp I can get retail is an Alto so I'll just order a GE one online then there will be no problems.

Thanks again.

I would say go with GE or Sylvania by what I have seen.