I've used sennheiser "big" shotgun mics (needing 48V phantom power and XLR connections) that are in the $700 price range and I was pleasantly surprised that the ATR-55 gave reasonable performance for the price.  You don't compare it to a 2 foot long mic that costs 15x as much and is clearly for professional use.  It's meant for the home moviemaker who is unhappy with the builtin mic on their camcorder which has an external 1/8" mono mic jack  -- yes, this is a MONO output so it will likely only appear on one of two channels if you put it in a stereo mic jack leaving the other one empty.  You might want to build or buy a dual mono to a single stereo adapter so you can capture audio from 2 mic sources on tape when using this.  It will give you more editing options later when you read your tape + 2 audio tracks into your software.