I'm sure this has been answered already, but I'm looking for an updated OPINION from the group.

I am pretty much sold on a new 2016 7.4 FX. The problem I have is my LBS only has a 17.5" frame on the floor for me to try. I am 5'10" with a 31" inseam. Any road bike I have had in the past was always a 55cm - 56cm frame. The 17.5" felt a little small but the LBS said that is the right one for me... Whats your opinion? Just for a comparison I went to a different LBS that sells Raleigh and tried an Cadent 3 which is almost exactly the same but their frames are 17" and 19". The 19" frame fit me like a glove and they agreed. So what should I do? Thank you all in advance for your advice.