The Lectro 400 series are what's called digital hybrid. What that means is they do not compand (compress and the expand) the signal when transmitting and recieving. This can give you a much more full & acurate sound. They also transmit with more power, I believe upto 100 mil-watts. Which will give you more transmit range and reliablity. The 411 receiver also has xlr balanced outputs and additional advanced wireless frequency filtering that can guard against sudden wireless interference from cell phones and the like.
Which mic will it come with?
The ZAXCOM ZFR100 records to a SD card with rock solid timecode syncing which is great if
you have a good timecode generator on your camera. You can always get a portable timecode generator if needed for that. Deneke, Ambient or Horita have quite a few.
There is no wireless so there is no chance for interference, drop outs or anything like that. The sound on them is excellent, really top notch too. This might be the best bet in NYC because of no worrys about the crazy wireless nightmare that NYC can be sometimes.
Another plus is the B6 is so easy to hide on clothing or in the person's hair.
Either would be a nice upgrade in my book. The Lectro 100's are nicer, but not that much nicer and might not be worth the extra money, go one step to either listed above.
The Lectro 200's are great too, but honestly I have not to much experience with those to comment with any real world use.