The derailleurs will work fine.
The aesthetics are the biggest selling point of the new Shimano line. But they are quite finicky. Due to the acute angles the cables go through to get concealed under the bartape, care should be taken so that the cables do not drag inside the housing. Good cable routing is key. Also, I spray lithium grease inside the housings before installation to keep them lubricated. Another thing - I once overtightened the clamp on the left shifter a little which compressed the ratchet mechanism inside causing it to not release when on the largest cog. Thankfully I was already on the last hill home when it stuck.
Personally, I like the look of the hidden cables, but it doesn't bother me with them exposed. I still have several older shifters that work perfectly well.