We found this awesome review and comparison of the 
- Model name XP7 Ultimate Cycle Light
- Configuration 7xCree XP-L LED
- Light output 3000 lumens
- Modes and runtime Boost: 3000L, 2hours Mid: 800L, 10 hours Low: 250L, 35 hours Pulse: 800L, 15 hours
- Battery 5200mAh 8.4V
- Weight 424 grams
- Price R 2,250.00
- Model name XP3 Performance Cycle Light
- Configuration 3xCree XP-L LED
- Light output 2100 lumens
- Modes and runtime Boost: 2100L, 2,5 hours Mid: 750L, 10 hours Low: 200L, 40 hours Strobe: 750L, 15 hours
- Battery 5200mAh 8.4V
- Weight 383 grams
- Price R 1,850.00
Mounting Both lights come standard with the new clamp quick release mounting system. Our XP3 still uses the familiar O-ring system but all current models will ship with the new clamp mechanism. I was very impressed with the clamp system. It held the light firmly in place without any bobbing around in the rough stuff. The clamp also allows for on the move adjustment (with some force) of the light's angle. The light can swivel on the clamp, a feature I used to look for wildlife in the bush and to turn away from the eyes of oncoming riders.
On my previous Extreme Lights products, the cable from the light to the battery was unnecessarily long for mounting on the bike. The XP7 and XP3 both come with a much shorter cable, which doesn't require wrapping around the bike to prevent it from hanging freely. Should you need a longer cable, there is an extension cable provided in the box. The battery packs are contained in soft neoprene pouches with sturdy velcro strapping for easy attachment to a bicycle frame The rubbery neoprene adheres to the frame and makes for a grippy fit with no sliding or movement mid-ride.
Operation Both the XP7 and XP3 are operated through the button on the rear of the light. The operation of the light is simple and intuitive. The only gripe I had was with the length of time the button needed to be pressed to turn the lights on or off but Extreme Lights have informed me that the timing of this function has been reduced. Double pressing the button activates the strobe mode.
The rear button also acts as the battery capacity indicator. The button remains green while the charge is above 50% then turns orange and later red when the battery only has 10% charge remaining. On the bike, Both the XP7 and XP3 saw a lot of action on my midweek rides up and around Table Mountain.
Extreme XP 7 Unlike the Extreme 2K and 1200 we tested last year, the XP7 and XP3 did not have a noticeable spotlight beam and better mimics natural light than the previous models. This has helped to reduce blind spots and unnecessary shadowing. In short, the quality of the light produced by the XP lights is greatly improved. I've always found that a light on the helmet is needed to comfortably ride single track. However, with the XP7 and XP3, I didn't feel as unsighted and managed to ride comfortably on single track with just one light mounted on the handlebar. I spent much of my rides on the lowest light setting while the middle setting was useful on slower single track, where the added intensity helped to better cast the light around bends. Although considering the claimed battery life, there's no harm in using the middle setting as your default.
The Boost mode truly lit up the night but unfortunately, it comes at a cost to battery life. When tested only in Boost mode, I managed to get around 90 minutes before the light automatically switched itself to a lower setting mode. The light could be forced back into Boost but as I still had some distance to ride, I decide not to chance it. Despite this, Boost mode is a great option to have when hurtling downhill, where every metre of vision is welcome. The medium and lowest settings claim to hold out for 10 hours and 35 hours respectively while the Boost mode is supposedly good for 2 hours. Extreme XP3 The XP3 is very similar to the XP7 in that it has a good natural light feel. The XP3 however has 4 less LEDs and, as you would expect, it struggles to match the intensity of the XP7. That being said, it holds its own and is perfectly adequate for most jeep track and moderate single track riding. Having fewer LEDs, the claimed battery life is improved over the XP7 with 2.5 hours in high, 10 hours in medium and 40 hours in low and should see you through an all-night mission.
Overall Extreme Lights have done a great in updating their bike light offerings. Both lights get a big thumbs up from me but if I had to pick one light it would be the XP3. It produces great quality light with an impressive battery life. Source: www.thehubsa.co.za
Source: www.thehubsa.co.za