The idea of the e gong is good and it does work although the sound produced is quite similar across a range of gongs, not a dramatic a difference in the sound produced as you would get from playing the gong conventionally.
However in saying the e gong does work well it does leave a lot to be desired in the actual design and finish of the product particularly considering the cost, the problem is that the end of the handle is finished very poorly as the plastic covering on the shaft is just heat crimped at the end leaving rough plastic tab which is very uncomfortable in use and if used for a length of time can actually make your hand sore. I would have expected this to have been finished off better, probably by having a foam or similar sleeve over it to make it more comfortable in use, this is something I am looking at to do myself.
As far as the product is concerned the idea is good and it does work but the actual construction doe not appear to have been thought through and although this might be acceptable in a product costing about 5 euros it is totally unacceptable in a product costing 25 euros, I am hoping that this is just an oversight in this particular batch, but if it is not then it is something the manufacturer needs to address.