Only problem I see with getting a 7-string as your first electric is that, if you don't have focus and a strong sense of direction and personality, you'll instantly become OMFGJEFFLOOMISDABEST.
That's because hitting that open B string repeatedly is kinda irresistible, while a 6-string is more...
Wassup!
First thing, I always avoid practicing unplugged.
You see, alternate picking and tremolo picking have been a problem for me ever since I started (14+ years). Recently I found out that I needed to apply less pressure on the pick, which makes building up speed a lot easier.
Which brings...
I took a long while to get into their stuff cause I was prejudiced against the radiohead and pop and non-metal influences.
Two years later I skip the breakdowns and screaming to get to the mid tempo cozy melodies and pianos and pretty solos.