The developers of the Flashlight XS app ($0.99) claim their app offers a performance breakthrough, turning an iPhone's light on instantly. This is predicated on "taking advantage of iOS 5 improvements and tuning to the latest hardware."
I offered to give it a try based on the passionate excitement of the developer's pitch letter. If a dev can get that excited about a flashlight app, then I wanted in.
First, I downloaded a handful of free flashlight apps and launched them. They all did what they promised, enabling the onboard LED for instant flash light access (there is some sample code in my latest cookbook if you want to roll your own.)
Then I tested out Flashlight XS. Like the other apps, it switched on the LED.
Did it do so noticeably faster or better? Er, no. Did it provide a "10x improvement in launch time"? No, again.
The latency was pretty much exactly the same as every other flashlight app I tried.
As to the app's merits, I think it has a pretty icon.
If you're looking for a Flashlight app, you may want to consider any of the free alternatives available on the App Store.
TUAW gives Flashlight XS a sad thumbs down down for promises beyond what it can deliver -- the light does turn on, but no faster than the myriad of similar free apps we've used. It's our considered opinion that the developers might not want to charge to do the exact same thing free apps do.