Hi! There is some overlap in the general theme, but AFI is mostly focused on staged pipe progression: different pipe, pipe-to-ground, pump, offshore pump, and pipeline extent upgrades across the game.
Advanced Fluid Handling does more with specialized underground pipe shapes, valves, underground pump variants, and routing tools, so they are not trying to solve exactly the same problem.
I did a quick compatibility check, and they currently do not load together because of a prototype upgrade-path conflict. It looks fixable, but I’m still building up my fluency with Factorio modding, so I’m not looking to expand AFI’s compatibility surface just yet. I’m definitely open to revisiting that down the road once I’m more comfortable with the modding side.
Thanks for asking!