I have tons of salads as go-to meals, and usually I buy heads of romaine and tear it up. But for convenience's sake, lately I've been using pre-packaged lettuces (like the ones from Dole). Are those a good choice? I've heard they have lots of preservatives, frrom both online sources and also from my husband, who is a chef. Comments? Should I stick with romaine or go to the packaged stuff? Thanks!