Booms on the KC-30A for example flow at about 4500l per minute whereas the Cobham refuelling pods flow at arounf 1450l per minute. Modern-ish fighters like the F-16 for example struggle due to pressure disconnect issues if the refueller tries to pump to much at once (generally only one pump used at a time for fighters) but can still in general (and entirely dependent on plumbing of course) receive faster from booms than the modern hose and drogue pods can deliver the fuel.Yes, not so much for fighters because the rate at which relatively small aircraft such as fighters can accept fuel is limited, & in many (most? all?) cases booms can transfer it faster than they can take it. I think that the fastest hoses (some are much slower) can deliver as fast as yer average fighter can take it nowadays.
Both hoses & booms are much faster than when the US SAC wanted booms to get fuel into its bombers at a good rate.
Dual mode has obvious advantages, but cost/benefit? Takes space (OK on big aircraft) & adds weight & complexity.
Aircraft wih internal tanks only are of course a different matter altogether and fill significantly faster than those with drop tanks.
Oh, and of course in bumpy weather boom refuellers also flow infinitely faster than hose and drogue...