As you read through this, keep in mind that a +VMI is a "Tight" Hitter environment and a (minus) -VMI is a "Reverse" hitter environment. 

The Tight Hitter is defined as one who hits the Four-seam Fastball of the pitcher at a higher rate than he hits the Sinker and the off-setting pitches normally used by the Sinker/Reverse pitcher.  

As you use this page you will see the Tight designation with a number following it such as (T  7.4) which means that in today's VMI Range this player hits the Four-seamer and its normal accompanying pitches better than he hits the Sinker and its off-setting pitches by a 7.4 score.

Note* If the hitter rating score is  high it may mean he is somewhat one dimensional, but if the VMI is extreme on the plus side, it may only mean he will hit the Four-seamer very well against a Tight Pitcher who throws a lot of them.  Be aware that in the extremely high VMI ranges, some players have little data, so these players may have high and low scores, as well.

The Reverse Hitter is the one who hits the Sinker better than he hits the Four-seamer and its typical accompanying pitches.

Note*  If a Reverse Hitter who scores high is facing a Reverse Pitcher in a large minus VMI Range, the hitter should do very well even though the pitcher normally has the advantage.

Extremely Important*  If the hitter score is extremely low it means that he hits both the Tight pitches and the Reverse pitches equally well.  If he is in the top tier of hitters he is obviously a quality hitter.  However, if he is not a Top Tier Hitter it could also mean that he is inexperienced in the league and may  still be proving his worth.

Your talent will increase as you decipher among the Tight Hitter high or low score vs the Tight or Reverse Pitcher score, etc. - but, the huge advantage you will have is in becoming expert at anticipating good games from the up and coming young players.