I have owned the 430EX II and the 580EX II. I have used PocketWizards, Cactus triggers, and the built-in transmitter in a 60D. None of these solutions worked 100% of the time and all had major downsides.

Amazing Flash, don't be fooled. this flash is the cream of the crop, so don't settle for anything less. if you do, its your own fault. lighting is the the key element to photos, so why would you go with anything less then the best?

Excellent! Very versatlie and multi-use flash - perfect for almost any situation and covers Canon's low-light deficiencies perfectly! top-notch prodecut and a very competitive price!

The battery charger that came with this is junk. It does not indicate when the batteries are charged. This means you need The battery charger is basically junk. It does not indicate when the batteries are charged. The bracket is a $16 item. The rest of the items are worth very little.

This is one of the best speedlights I have ever owened. Built quality is extraordinary, light output is amazing. I recommend this unit for indoor /event photography.

Powerful; fast recycling

bulky

The radio system lets you easily control all your flashes from the camera with some using TTL and some on manual and even switch modes without having to touch the flash. It's just amazing.

Supports both radio and optical triggering, so if you have the 400EXII's you can slowly convert over without having to buy a radio transmitter on day one; Great power and good batteries will last for quite a while

Price

This flash was well worth the money I spent on it over purchasing one of the cheaper ones. I'm not an advanced photographer but I am learning. I've also bought the ST-E3-RT which compliments this flash making getting the flash OFF the camera and into a place which is actually useful a breeze.

Easy to use; Build quality; Screen size

Complicated; Bulky

I've been an international photographer for over 11 years now. Just switched back to Canon after 6 years with another brand. After all that time I just never bonded with the other brand. I love the quality I get with my Canon system over any other system I've ever used.

I bought my 600 EX RT in late 2015 after I thought my 550 had been stolen, so this is really not a case of an upgrade, just buying a top of the line flash out of desire for the most options and reach.

I am very satisfied with all the features.