I recently took delivery of a Pixapro CITI 600.
As a portrait, event and occasional wedding photographer I need reliable portable lighting that isn't too bulky to be moving around as and when required. I looked into the manual version and although it would do the job there are occasions when TTL is desired. It is also a very unit for high speed sync as the transmitter goes above normal sync speed the unit automatically goes into hss unlike my AD360 where a couple of buttons need to be pressed and a different transmitter/receiver set up is required.
Some photographers believe that TTL is the same as putting the camera in full automatic and there is no user vision in the images shot this way, I think that is down to the photographers not understanding TTL and it's uses. TTL basically takes a reading of the scene and decides how much light is required to light the scene correctly, if I feel the scene is slightly over exposed I can dial down the power of the TTL so less light is used, if I feel there is not enough light I can dial up the power so a little more is used. This is known as flash compensation.
TTL comes into use when situations are changing such as intermittent cloud cover or subjects moving closer or further away. In manual as the subjects move you would need to keep adjusting the flash power to keep the image properly exposed but TTL does that for you.
Fix it in photoshop is an answer I get sometimes but when shooting an event and printing on site photoshopping each image is not an option especially when getting it right in camera is so much easier.
I first used the AD600 on a lighting workshop run by Mike Weeks and Brian Muir, I was very impressed with the build quality and the ease of use. Four of us shot for a good few hours and the unit never missed a beat or went into overheat mode when using HSS. I had already been looking into buying one of the units myself since its release but was a little hesitant over what it would do that the AD360s wouldn't.
I went for the Pixapro branded unit as there is full UK warranty, not that I think I'll need it as my other Godox products have been great, but the main thing was the free transmitter and 120cm octobox. I already own a few Pixapro soft boxes so I knew the quality of the product.
Credit: Mark Elsworth - Website: http://www.markelsworthphotography.co.uk/blog/2016/8/pixapro-citi600-godox-ad600-review