I use bibs myself and like them better than just shorts. Like 79pmooney above said it really comes down to personal preference and what type of rider you are. In my opinion the bibs usually are about $12 to $18 more than their shorts counterparts and that extra amount never bothered me. One other thing many people will forget to mention to you is get some chamois cream as it helps with chafing if you experience any as well as preventing hot spots. It has made a noticeable difference for me when going over a distance of 15 miles.
GOOD LUCK!!!!