If you're looking for big-picture advice, there are a couple of key advantages to going the fee-only route. First, you don't have to worry that your planner will limit her recommendations to those investments that will line her pockets and empty yours. Second, you get a better idea of how much you'll be paying for advice.
But there are differences in how fee-only planners bill clients - some charge flat fees while others charge a percentage of the client's assets. And there are potential perks and pitfalls to hiring someone whose paycheck depends on what you're worth. On one hand, they have great incentive for you to make a lot of money. On the other hand, the setup gives them an incentive to urge you to invest rather than pay off a mortgage or other debt. So these planners may pay more attention to assets under their direct management rather than a client's entire financial situation.
For more see How much will a planner cost me?