I recently bought a nice bike. The local bike shop here is extremely knowledgeable. All of the employee's are, near as I can tell. That said, when I bought the new bike, I had narrowed it down to the exact bike I wanted by searching online. In other words, the floor guy had no influence on the bike I bought. I say... Study the specs on paper. Study the geometry. Ask questions here.
I walked in and I said I want to look a Specialized E5 Comp in size 52cm. He showed me the bike. I stood over it. Perfect. I asked for the specific color I wanted. He disappeared for 5+ minutes and showed up with the exact bike and color I wanted. I stood over it and said.... Sold.!!
It's up to the buyer to decide which bike he wants to own. In this day and age, if you have the basic smarts to decipher specs and geometry, you can decide on which bike will fit you best on a computer sitting in your den. I'm a dummy but that's how I decided on the exact bike that would fit me best.
Further more.... It came down to a Trek CheckpointALR or the Secialized E5 Comp, online. I wanted the Trek but I could see on paper it wasn't going to be a good fit. Guess what.?? I was right. It didn't fit. On the other hand, I KNEW the Specialized would fit just by reading the specs and geometry, online. I went to the Trek shop first, ruled out the Checkpoint, it didn't fit, then headed over to see the E5 Comp and I was sold on it in 15 minutes.
I literally didn't have any technical input from the guy on the floor. I did my homework. And NO test drive other than on an indoor trainer on the shop floor.
Oh my, what a bike..... Wow. Love it.!!