Choosing a bowling ball depnds on whether you are a casual, once in a while bowler or bowl regularly in a league or tournaments.

The surface material of the ball is probably the most critical aspect to consider in purchasing a bowling ball.  This determines the friction on the lane as  the ball travels down the lane.  More friction gives more hook.

Following are the different types:

Polyurethane or plastic--Great for beginners.  Has the least friction.  Fairly inexpensive and easy to control.

Urethane--Gives better pin action than plastic and has more hook.

Reactive--Called this since the ball reacts to the lane surfact.  Good pin action and hook.

Particle--Designed for maximum friction and maximum reaction to the oil on the lanes.  Good for bowling with a high  speed ball.  This ball has minute particles added to the surface which has a grabbing effect on the lanes.

Whatever type of bowler you are, having the right ball is very important.