I use a combination of Premium, PC and Classic:
1. Premium for logging most things during the day
2. Classic when I have to search for a meal I know I've had a while back and can remember one of the ingredients. That way I can just pull the entire meal out of the archive (say for example if I got a certain platter at Famous Dave's but don't create a new food for it)
3. PC for logging, trending and doing deeper analysis. Also, because FitDay website activities don't show up in FitDay PC but FitDay PC workouts do show up in Fitday website, I do all my workout logging in there too.