Humminbird 160 or 170?

First finder for me. I've seen lots of positive feedback on the forum for the 170. All I can find in the stores is the 160. I fish freshwater lakes, usually no more than 100 feet deep. Should I settle for the 160 or order the 170 online?
Thanks

I think mine is the 160.  It's an inexpensive option.   I mainly use it to show me the depth and whatever the bottom is composed of ie rocks or mud. 

It has marked fish at over 140ft at times.  I usually am not in that deep of water.