What specifically do you need the system to do for you, under what conditions? Actual numbers (at least guesstimates) are required to provide realistic feedback. Without numbers, I can only suggest that you put your conditions/etc into one or more of the various calculators and simulators out there like the ones at ebikes.ca to see what power levels you *actually need* to do what you want to do under your specific conditions. You may need more power than your existing parts can supply to do what you want.
Some notes:
Range isn't determined by the controller, it's determined by the battery size and your usage under your specific conditions.
Power needed is determined by your specific usage under your specific conditions.
Higher speed takes more power, so you'll get more range by going slower.
Efficiency is unlikely to vary much for any specific controller vs another; it's more about your usage and your conditions vs what the system was designed to do. If it's made to run at a certain speed on the flats, pushing it harder may put it outside the peak efficiency of the parts (but realistically the designers probably placed zero emphasis on efficiency).
Some motors may be more efficient than others, when used within specific usage scenarios and motor RPMs, but most of them dont' have this data (dyno sheets) available so you can't really compare them.
Batteries that say they're capable of really high currents vs their capacity often aren't, really--most of them will have a lot of voltage sag under those loads, so you don't get nearly the power out that you expect, or as high a speed (since hubmotor speeds are affected by the voltage provided), and the cells and interconnects, BMS, etc heat up more than they should. I'd venture that most of them don't really handle more than about twice their capacity rating as amps (also called 2C), regardless of what the sellers claim, and some much less than that.
VESC is probably a good controller type; it's very tunable to various systems. It does require that you tune it for your system parts; it is not a plug-and-play system. I don't know what each specific brand can or can't do, whether it has the features you want, or how good their support is--those are things you'll have to check for each one you're considering buying. As long as you can use VESCTool to set them up, though, you should be able to change any of the settings you need to, and tune them to your motor, battery, etc, as required. And it's opensource so if you know how to code you can alter the software in it to do what you want, assuming the seller adhered to the opensource standard and provided the code, schematics, etc that they used (not everybody does things the way they're supposed to).
I have a scooter right that has a motor that's rated for 2000 w 48 volts. It's a 10-in... I'm using a cheap Chinese controller that says it's 2,000 w and it is an 18 mosfet... The battery I'm using is a lithium ion and it's 16 amp hour and rated for 100 amp... I know that that controller is a complete POS. I paid about $30 for it and it works horribly.. motor is a sensored motor and I'm wondering what controller I should switch to... I've heard a lot of great things about vesc.. I'm wondering if I should switch to a flipski 75200... The 75200 Overkill? Or are there other controllers in that range that are much better? I'm looking for top speed and obviously efficiency something that will give me a good range. I've really only used a lot of the cheap Chinese controllers that I bought off Amazon and eBay, and honestly they've all burnt out very quickly on me, especially if I've modded them in any way... Does anyone have a recommendation on a good controller in that range? Someone told me votol was good for fairly inexpensive price .....