If you've only ever gamed with CT crapsoft then you may find you are more outgunned then you would like using just a pistol.
Pretty much 90% of all hits in airsoft are made from a flanking/covert position, at least when played outdoors.
The guns just don't have the range compared to how far off you can identify the enemy.
Pistols can be a lot of fun, but you really have to know when to hold fire which is basically any time the other player can see you. This is fairly true of all airsoft weapons, just more-so for pistols.