There are many differences between halides. In general all 150w halides will be of the same technical specification across the industry in terms of size, fittings and lifespan. This goes for the 250w double ended and single ended bulbs.

If referring to the colour temperature of Halides(Kelvin Rating) these can differ from one manufacturer to the next as it all depends on the makeup of the pill used on the inside of the halide during manufacture. Therefore no 2 manufacturers 10k halides will look the same.