I already have an EBMM 7 string so there's no issue with the extra string. In fact the low B opens up so many doors when it comes to lead and shifting patterns around the fretboard. I don't like playing off drop D anyway, straight forward power chord shapes with standard E to E tuning is what I've grown up on. Add a low B in and things get very interesting. Besides, changing from standard tuning if you want to sweep arpeggios over 6 or 7 strings is making things unnecessarily difficult on yourself.
Re the heaviest guitar sound... you obviously haven’t heard Meshugga! 8 string guitars and they are down tuned a whole tone. The tone is so heavy that it has the same effect as a techno bass line when it comes to pushing air on front of speakers :eek: