I made this exact move about 7 years ago. Cleaner look, poorer shifting on the RD in particular - slightly higher effort and a little less crisp feedback. The other potential negative is that the x700-series shifters have a reputation for eating cables (I never had a problem with that, but @
datlas can attest to it). Prolly safe to blame the new (at the time), tighter cable routing for both of these niggles.