I haven't voted yet, and I am going to have to think about this. Either L3 or fast L2 would only be of use to me on the rare occasions when I need to charge away from home. L3 would certainly be more convenient, but for the foreseeable future it will also be much less available. Not getting L3 was an easy choice when I ordered, since it would have cost me $1640, rather than $700. (I didn't see much value in any of the extra SL features, so would have had to upgrade from SV just to get L3.) If I could have gotten L3 for $700 I might have done that. On the other hand, it appears that L3 charging may be a bit rough on the battery. On the other other hand, I'll probably lease anyway, so I would have three years to decide how the battery is doing.
I think I'm glad that I wasn't really faced with either of your $700 choices. Tough calls, indeed.
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.