Both are good units. I would say it all depends on your fishing style. If you hop around alot you are going to want the less heavy lx-6. If you mainly stay put, go with the lx-7. Also if you ever plan on upgrading and adding the camera to it, the lx-7 size is nice to have.
I have hole hopped with a lx-7 a few times and it works fine it is just a little clunky.