If you feel the reach is better on the M size, then stay with that. For me, I think reach (or virtual top tube length) is more important than seat tube length. I like to be a little more over the front wheel by using a 120mm stem. Also like said above, I also don't think that 4.3cm saddle to stem drop is huge. But you need to set that based on your flexability. So a "professional fit" like the Specialized or Serotta fit systems should help with that.

Edit: Another personal preference for me is that I like to see the front hub when I'm in the drops. Will vary on bar type, but I stull use an older deep drop style of handlebar. Also selected the widest bar I could get: 46. Its comfy but I think I could use 44 without any probs as well.

Yeah, its more of a tough decision because going to a M/L would mean more of a hassle. I got the defy advanced 2 for 1500 on a '16 closeout (usually is 2100) so the more I spend the more it won't be worth it with the "saving-on-a-closeout" mentality. I paid $50 for the basic fitting yesterday (fitting me to a M) so on top of that I'd pay an extra $210 to swap for the M/L, which is most likely too big in other areas other than stack. It doesn't help that looking at the M just looks small. The M/L at least LOOKS like it would fit me. But I hear thats because of compact geometry.

First bike shop: "We can exchange it, but I highly highly advise against it. We looked at your scan / numbers again and other guys here said you should be on a M"
Second bike shop with basic fit on the medium: "I would put you in the M/L if buying from us, especially if you don't want a lot of drop." - Never was reach even talked about. Only a brief "the M/L is only 1.5cm longer".

Alright guys, I think I'm going to just keep the M and possibly flip the stem when its being built up tomorrow.

Flip the stem up if its currently flipped down, yes. Try a new stem also. Try a stem with quite a bit of rise in it to bring the handlebars up, particularly if your having neck issues. Changing stems is just par for the course when trying to improve fit.

Years ago elite racers didn't have that much drop from saddle to bars. They reached forwards instead and/or bent their elbows when riding. The modern trend is to ride with straight arms when in the drops. Personally, I prefer the older way of doing things.

Anthony

Good call.

So I was looking at other similar bikes geometry, and looked at the Trek Domane in size 56. Whats funny, is the frame reach on that bike is EXACTLY the same as the frame reach on the defy medium (54.5 size). 37.7. It also may explain why other mfg's sizing charts suggest 5'9" height being the cutoff for a 54, while Giant says medium goes all the way up to 5'11" height. The specialized however, run longer reach on both sizes for the robouix