Like you, I was probably sceptical about whether this cut-price item could do the job, especially when compared to it's higher-priced cousins from the Canon and Nikon worlds.
I needn't have been concerned!
The wireless transmitter and receiver performed flawlessly, every time, although it did begin to falter occasionally after a 20-foot-plus distance. Understandable, I suppose, as none of them work flawlessly up to the (maximum) distance stated, in my experience.
But for small to medium distances, this combination is very well worth the money! Quick response, and I had no trouble with frequencies - although you can change the frequency range to one of 4 possibles, just in case your neigbour's remote controlled garage door is causing interference!
Lightweight and reliable, I'd recommend these to anyone.
Now ... if only I could work out how to set flash power properly when firing remotely, I'd be laughing! :o)