Chinrests come in different shapes and forms and is a very personal choice. If you look at all the violinists in an orchestra you'll notice that some have side-mounted chinrests, others have center-mounted chinrests. I personally prefer the center-mounted chinrest, as it helps to position the violin higher on the shoulder. For beginner students it may also help to position the eyes closer to the A and E strings and prevent a student from tilting the head to the right in order to see the strings better.
One of the most difficult skills to master when learning music is to develop a feeling for the pulse of the music. Until now we have always used a metronome, but it takes a while before one can translate the clicking sound to actually "feel" the pulse while playing the music. Lately more products have come on to the market that will help a lot with this, as it is placed on the musicians body, where the pulse or beat can literally be felt.