I started with one a few years back when we decided to get serious about ER, we were skittish following 2008 and had just been saving cash.
I went with someone that manages for several colleagues so had a reference. We've kept our 401k's self managed, so he worked with the other third of our portfolio. I was also extremely risk averse in my guidance. We've done far better than cash (1% banks) but not as well had we put that third into index funds...but at the time I would have said NFW to that and wanted this to be our safe pre-59 withdrawals account.
We got what we paid for, and what we asked for. I've since had the AA shifted and improved my risk outlook, and it's become more of me directing vs. him advising, so it's only a matter of time before I roll it all over to Vanguard. I've also applied what I've learned here to my 401k, such as it is with my employer options, but will be rolling that over to self-manage next year once my severance ends.
If you really have no idea where to start, in retrospect, take a few months to really read up and learn, and ultimately you can do far better yourself. But if you're not sure, don't have the appetite, then find one that charges as little as possible, comes with references, etc.