How are they "quite similar?" the only argument I can think of is that "they are both wooden coasters" and if that's your basis alone.........fine I guess, regardless, the trains are different, The Voyage has a steel structure and goes up a hill and then comes back down that hill, also features tunnels. The other has a cable lift, a 76 degree drop, airtime hills that feel unlike any other coaster I've ridden, sits on flat terrain with 0 tunnels, and typically rides much smoother than Voyage. Both made by different engineers and El Toro was laser cut and built like a lego set, while the Voyage was...........not built like a lego set.
Also I don't think either are "overhyped" both are considered two of the best wooden coasters in the world and based on my rides on them, that argument absolutely stands.