Cam sensor difference?

[ToeKnee]

I'm going to replace one of the cam sensors in the M278 engine in my SL as it's just started to leak oil and there is a large difference in price between the genuine Mercedes sensor and an aftermarket one. My question is, considering how a cam sensor works, why would there be such a price difference, can a cheap one be made badly? Surely a cam sensor will either work or not so shouldn't be able to be made badly?
I have no problem paying the full price I'm just curious about how quality could be different from someone on here who will know more about it than me?

 

[Dodipops]

Lower quality materials in the windings and less of it.

However a good aftermarket brand will be cheaper and still as good quality.

 

[SpikyMikey]

A Hall Effect device is relatively simple; I'd imagine as Dodipops says a decent aftermarket item, maybe Bosch or Hella wouldn't be a problem.

 

[ToeKnee]

Thanks both. I've looked for a good aftermarket one Bosch etc but cannot find one that corresponds to the right Mercedes part number and cannot find a search section on the Bosch website for cam sensors. Strangely, the original one is stamped "Continental" but cannot find one of those either.
Again, thanks for the replies.

Ps the part number on the original sensor is A2761530028

 

[SpikyMikey]

Thanks both. I've looked for a good aftermarket one Bosch etc but cannot find one that corresponds to the right Mercedes part number and cannot find a search section on the Bosch website for cam sensors. Strangely, the original one is stamped "Continental" but cannot find one of those either.
Again, thanks for the replies.

Ps the part number on the original sensor is A2761530028

Are the real deal MB branded ones excessively loaded with 'Badge Tax' ? If not, I'd be tempted to stick with that.
Having said that, I had a mix of Delphi and MB ABS sensors on my 204 without any issues.