The two bands' music (songs without the vocals) is completely different, albeit the same MHR genre. The two lead guitarists in no way sound the same.

The vocals are similar, but the lyrics comparatively are not similar at all.

So what it really all boils down to is that ER and HS have similar vocals. ER were formed from a band called Pain, which was more of alternative band. I own one Pain CD, which has the same vocalist as ER, and the vocalist sounds the same in both bands. In ER, the vocal arrangements have changed to match the MHR genre. Now the fact that both ER and HS vocalist sound the same is more of coincidence than a devious plot to be as unoriginal as possible so as to win over fans of the older HS CDs.

I am surprised that since the topic originality was brought up that no one has mentioned that the much beloved two first HS CDs are not that original in the MHR genre. Harry Hess admits as much.