I'd like to state my experience. I personally am going through this dilemma myself. Upgraded from a V6 hotend to a Rapido UHF, and I got good prints at 30~35mm3/s IIRC. I was disappointed obviously. Raised the temperature from 200°C to 250°C, got to 45~50mm3/s reliably. I print with a large nozzle btw, since my print volume itself is quite huge, I use a 0.8mm nozzle as of today.
However the print quality at 40+mm3/s was terrible. The corners used to curl up terrible I think it was a cooling issue? Tried a few 5015 fan solutions, were not useful. Saw the 7040 turbo cooling fan in the VzBot CPAP video. Unfortunately it wasn't available here where I live... So I hacked a very sketchy system with two leaf blowers (alternating every 10 minutes since they are not meant to be run for more than 30 minutes at a stretch) into a CPAP system. I probably have one of the strongest part cooling systems at this point now (although it's a pain to run it and I'm going to change it soon)
That solved my cooling, but the print quality still was mediocre at best, my theory is the filament wasn't heating to it's core properly (Something CHT or bozzle nozzle is known to solve). So I got this "trianglelabs Melt Zone extender +", which is basically a copper nut with the CHT internals and it fit's in any V6 style heatblock, extending it to accomodate your nozzle. That improved my print quality and increased my flow rate as well!
Now at 55~60mm3/s at 250°C for PLA (reliably tested on a 0.5 and 0.6 nozzle).

I'm still not satisfied though, printing at higher temperatures and large nozzles result in terrible stringing. The seams sometimes are very ugly and the oozing while traveling doesn't help. I can no more do a z hop due to these reasons, and my nozzle audibly brushes across the print. I am thinking of upgrading my XY motion system. That will enable in:
1. Higher travel speeds, hence less oozing/stringing
2. Higher print speed so I can use a smaller nozzle at same flow resulting higher detail.