Not to mention that the real, laser-based HWS' are more than bright enough to use outdoors on the sunniest, brightest day against the most well-lit backgrounds you can imagine. Whereas, the LED-based replicas will totally wash out in those situations. Conversely and as already mentioned, the genuine HWS' emit absolutely zero light forward toward the enemy unlike their LED counterparts. Definitely a comfortable advantage in none/low-light ops.
What it boils down to is a simple acquistion cost (affordability) vs. desired performance equation that only you as the shooter can solve for yourself. Whichever way you go though, take heed of the lens protector advice already offered...you do
NOT want your optics to be shot out.
Personally, I have both a genuine 551.A65 and one of DragonRed's clone LED-based versions, but that's just me.
Good luck with your search,
'Fly