Is there any difference between one manufacturers bulbs and another manufacturer's?

What if any difference is there between the lesser expensive bulbs say like a 1000 hps for under 50 and the ones that cost 70-80 and one I think is called Agrosun for 120.00? Sunmaster and Hortilux I had never noticed any difference.
Is it manufacturing hype or fact that some bulbs will work better for plants than others? With all the hype these days and paying extra for nothing for many things I'm wondering if grow bulbs fall into the same group. If anyone has documentation on tests or some kind of proof of differences I'd very much like to read it. I'm only interested in facts however expert opinion by those formally educated in horticulture or professional growers/farmers will be appreciated. Thank You

Some bulbs have more advanced design but I have no proof of special results. But if you can find 1000w HPS bulbs, please tell me where.

Only difference Ive found is 15000 extra lumens for 70 bux. heres alot of info on hortilux...http://www.budbook.org/HighBreed/blog/29/

Thanks for the chart!

i've seen sylvania and hortilux grows of the same strain and conditions in the same room, and hortilux was greatly superior