All I can say is I have 600EX-Rt x 4 and the ST-E3-RT
and I don't know what more I can ask for.

Works all the time every time.

But as I posted in a earlier thread,
To take advantage of the GROUP function you need a 5DIII or greater body.

4 flashes may sound like overkill but I sometimes double up on the main light and use one for a background and one for the hair so that equals 4.

Could not be happier with this set up.

I find not having the bulk of a 600 EX RT on camera is liberating.

If you are considering it go for it.

Can't speak to the YN E3 RT but after the ST E3 RT I never looked back and sold my other collection of triggers and my 580s


Syl wrote on this combo last year and I hope he updates his book.

Thanks