I’m still using the Yongnuo RF-602 radio slaves that I purchased back in mid-2011. I was still shooting with Canon gear then, so the 602s have survived not only 4 years of service, but also the transition to m4:3, and all without so much as a hiccup. I depend on them and they’ve never let me down.
I wrote a review of them back then, which I added an update to sometime later, saying that in my opinion, the 602s are the “best-bang-for-your buck when it comes to fully-manual systems.” I still stand by that, although I don’t know if the 602s are even still available. At some point in 2011 or 2012, I bought another set, so I’d have a spare Tx and five Rx, in hopes of being able to use them long after they went out of production. I think Yongnuo may be up to the 604 model now, or maybe even further.
It’s worth mentioning that in all that time, I’ve never had to change the battery in the Tx unit, and have only changed the AAA batteries in the Rx units maybe once a year. They’re just unstoppable.
But every so often I take a look at the radio slave market to see what’s new, and which players are still around. RadioPoppers seemed like an interesting idea at the time, and they’re still around. So are PocketWizards, of course. (They may be considered the “industry standard,” but I still think they are grossly overpriced for what they do, and especially their basic “dumb” models.)
Cactus – another of the Chinese brands – released a new system that claims to offer power-level adjustment for several different brands of speedlights, including Canon and Nikon, as well as – depending on which ad you read – possibly Olympus and others. In addition to the transceiver units, their system also includes a speedlight with a built-in receiver, that is also fully adjustable from the Tx unit.
This is a rabbit hole I often get sucked down, thinking how nice it would be to be able to adjust power settings right from the camera – and especially when I’m using the octabox, with the speedlights inside, behind the diffuser panel. But does the convenience justify the expense? Well, not really. Not in any of my flash setups.
So the verdict at the moment is: there isn’t anything out there that is really going to beat my solid old 602s in terms of both cost and performance. And especially considering that very few of the “smart” radio slaves systems are compatible with Olympus to begin with.