At 6'1 - 34" inseam... I'm "supposed" to ride a 58, which I have before. Sat on a 56cm and it just felt right. That being said... My seat height is about 1 cm away from the max recommended on the frame. The stem length was just fine at 110mm. I went to a compact handlebar and needed to increase it to 120mm though.

One caveat... the 56cm bike came with 172.5mm cranks... the 58cm with 175mm cranks. It's going to be a little extra cost at this point to get that changed to 175mm with my inseam length.

All depends on what works for you...