This subject is always going to divide opinions. I think most of us know exactly how it works, it effectively gives a bigger throttle output for less pedal travel.
Does it give more power - No (but I don’t think anyone is claiming it does)
Does it make the car faster - No (but I don’t think anyone is claiming it does)
Does it ’feel’ the same as putting your foot down further - In theory it is the same I.e. throttle output increased for less pedal travel, but, does it ’feel’ the same - No it doesn’t. It’s difficult to explain ‘feel’ , and people will disagree with me, however I bought one for my auto 370 years ago because the throttle response felt ‘dull and slow’. I DId Not buy it to make the car faster (or even feel faster), more powerful etc etc, I bought it to improve driveability by improving throttle response. For me personally, and it is only my opinion, it made a huge improvement to the driveability of my car. Since installing it I’ve let loads of people try it and every single one has said the car drives much better with the sprint booster on.
There will always be people who through personal experience or just opinion will disagree with my points above, and I’m not saying I’m right, just stating my opinion.
If anyone is thinking of getting one I’d say try a car with one installed and make up your own mind - at the end of the day that’s all that matters.