I was always nervous about going to clipless... honestly they scared the crap outta me. One day I just decided to give them a shot; i immediately felt the improvement, but it took a few rides before I felt "comfortable".
Now... i can't ride without being clipped in. I don't like not being able to "pull up" during my pedal stroke especially when climbing!. And more importantly, for those "scary" technical sections I don't feel confident unless i am clipped in.
What it boils down to, you need to give it a shot. Your experience may be different than mine or anyone elses who have responded. If you decide you don't like them and want to go back to flats, no big deal... do it. But make sure you give them a few good rides to get comfortable.
FWIW: I started out on SPD's with the standard cleats (not the beginner cleats) and adjusted the pedals for their easiest setting. After one season like that I adjusted the pedals to their hardest setting and have been riding like that since. And now, I finally decided to give Time pedals a try... didn't take them on a good ride yet (doing that today), but during my "learning" session in the yard, i really like how the engage/disengage feels vs. the SPDs.