YES! THANK YOU!
I frequently refer to 2600 Space Invaders just as you have.
With home play being a bit of a different animal than arcade play,
Space Invaders 2600 changed the arcade version a bit to actually make it more fun to play at home.
Ever played MAME Space Invaders? It gets boring a lot quicker than the 2600 version, IMHO.
Without the incentive to get every last second of gameplay out of a quarter,
some MAME/'Perfect' arcade games aren't as much fun at home as they were in arcades,
and a FEW home conversions made the right choices to compensate.
Other times perfect conversions are the trick(pac and ms pac, etc), but,
well, I could go on and on--you get my point.