I have one. For my purpose I didn't like it. For your purpose it may be great. I thought it would be nice to record with, but it didn't do a very good job for a variety of reasons. The other thing I am not keen on is that I hunt hogs at night. Any light is not good IMHO...so a lit up phone can be an issue. Regardless, this could something workable for you.
Something else you could try is to get one of the digital scopes with a video out and hook it to a small LCD screen. Just a thought.