I have to say, I've been waiting on this song for years and it didn't disappoint.
To be honest, it's not my favorite Dream Theater song, but that's like saying something isn't the best steak or poutine, even the stuff on the lower end is still great!
As with many (if not all) Progressive songs and especially Dream Theater, the chart is all over the place in a good way, mixing simple strum patterns and basic hammer-ons/pull-offs all the way up to two particularly complicated and extended sweeps and odd riffs and everything in between.
Honestly, I'd say that it doesn't deserve top tier in difficulty if not for those extended sweeping patterns, and even then I'm not sure if they last long enough to make the song that difficult, as it doesn't get frustrating or overstay its welcome.
All in all, a very well balanced guitar song, difficult without being frustrating, lots of variety despite its long running time, and it's Dream Theater's single big hit, so it won't be hated by anyone.
5/5, get this song no matter what instrument you play!