Unless you're into radio mics, longish guitar leads leads are a necessary evil — even the best leads have both resistance and capacitance which affect the tonal quality of the instrument. Also, if you want to record the guitar without going into an amp, you still need to use some form of DI box as an impedance matcher — unless you happen to have an active guitar.
The idea behind the Active Lead is to kill the proverbial two birds with one stone by providing electronic impedance‑matching at the guitar end of the lead. Because the output impedance of the electronic impedance‑matcher is very low, even long lengths of lead can then be used without affecting the tone of the guitar. There are those who claim that the capacitance of the guitar lead resonates with the inductance of the guitar pickups to enhance the tone, but as there's no way of knowing exactly what type or length of lead a specific guitar was designed to work best with, I tend not to worry about that too much. In any event, if you're DI'ing using the Active Lead for recording purposes, the chances are you'll be using a clean guitar tone, which generally sounds noticeably brighter and livelier without the impedance loading of a conventional lead. If you're using overdrive, then your preamp will act as an impedance matcher and you may find the active lead doesn't make any significant difference. Even so, it's worth trying, just in case it does!
I've reviewed active leads before, but this one is battery powered, which makes it very convenient to use. It runs for around 1000 hours from a PP3 battery, and used with my PRS guitar, it delivered a vibrant, sparkling tone with no trace of noise. The PRS is capable of putting out very high signal levels but I was unable to overload this device. A small LED is fitted to the battery box to show you that the lead is powered up, and a recessed slide switch is used to turn the power on and off.
At £45, the 6‑metre Active Lead is a viable alternative to buying a DI box for recording both guitars and basses (longer versions are available at a slightly higher cost), and because it runs off a battery, there's no hassle with phantom power or ground loops. If you don't have something like this already, I strongly recommend it for recording any form of clean electric guitar or bass.