Re: replace AT835b with Senn MKE 600 or?
 

Take a look at the AT 875R. I recently got one to replace my Rode NTG 2. The AT 875 is much more sensitive then the NTG 2 and sounds quite good. It does need phantom power though. It is very short and fits on a camera nicely. I wanted a more sensitive mic so I could keep the gain down on recorder or the camera. I also bought a Sennheiser MKE 600 because the specs say it is even more sensitive then the AT 875. In my tests though the MKE 600 wasn't as sensitive then the AT 875 and the sound was only very slightly better, so I ended up sending it back and buying another AT 875. The MKE 600 is very nice though and will buy another one soon, so I have a battery powered option. It has better side rejection the the AT which it should being two inches longer. The battery indicator light and on off switch is also nice. Here is a link to a comparison review MKE 600 vs ME64.
Gear Lab #4: Sennheiser Shotgun Showdown - The ME64 vs the MKE600 - The Location Crew