Looks like myri and pnnv is the exact copy of preev.com. But the closest one is myri as it has the other conversion too from other cryptocurrencies which preev has.

Btw, I don't know what rhombus is and I haven't seen that when I've used preev before.

As pnnv is doing its signature campaign for a month, I think that it'll contribute for the impact of their traffic. I guess myri should also the same if it has some budget since the co-founder has also commented here.