Heists are perhaps the most exciting and original missions in GTA 5. The mechanics of their work is directly connected with the selection team. The more experienced a certain specialist (stronger than filled his strip skills) the less is the chance that he let the team down. But the proportion of production of such a team member is much higher than his less experienced but cheaper counterparts.
Each participant in the robbery, is responsible for a certain part of the operation. Hacker engaged in computer security systems, cameras, alarms and other things. Good shot useful where it is assumed a large amount of security guards or police, and experienced driver will be able to save the team or prey during the chase.
This means that the choice of the team depends on the type of robbery. During a daring RAID in broad daylight with shooting and breaking jaws more useful would be good fighters, but if you're going to get to the goal clandestinely or under someone disguised, the more helpful will be skilled hacker and driver.
Be careful in this matter, since the error one team member can cost a fair share of production for all others. For example, in the first robbery, if not a very experienced driver, he will crash while fleeing on motorcycles and if the player does not manage to catch them on the go, dropped the bag with the money, the team will lose approximately 25% of the profits.
All available team members gain experience for each successful robbery, of course, if they survived it. So inept hacker, by the end of the story the company can turn in strong spices, which should not be ashamed to take even the very difficult and dangerous business.
Because after all the story the heists can be replayed again, you will be able to try different combinations, and "pump" all available bandits.