Using a Nikon D40, the Cactus V5 synchronises up to 1/1000 second. At 1/1250 only a small portion of the flash light is captured, and at 1/1600 only a negligible amount is visible. With a Nikon D700 I get clean frames up to 1/250 second, the maximum sync speed for that camera. You can compare these results with other flash triggers in this article.
I was able to fire at 5 pictures per second, as fast as my camera and flashes are capable of taking pictures.
In shutter release mode, if you hold the transmitter button down for more than 2 seconds then you can keep a camera shutter open in bulb mode until you press the button again. This is something only certain triggers offer.
Medium and long ranges are no problem for the Cactus V5. I haven’t done a full range test yet, but other beta testers report maximum ranges of 150-180 m (500-600 feet) in cold winter temperatures. This is typical of 2.4GHz triggers and probably more than you will ever need.
At very close ranges, the V5s are specified not to work well under 30cm (1 foot) or so. I found that this is indeed the case. Within about 10 inches, they just don’t work at all. This can be frustrating when doing close-up and macro photography.
The Cactus V5 feels reasonably well built, made of sturdy plastic with no creaking joints or obvious weaknesses. I haven’t handled the V4s before, so I can’t compare, but it is many times better than the unwieldy V2-generation triggers. Because of their size, they might be more vulnerable than a compact trigger such as a Phottix Strato, but it is impossible to tell without using them for a long period of time.
On the male foot, the locking ring is very stiff, but the manufacturer informs me that this will be fixed by the final version. The foot itself is made of metal.