To be honest I didn't expect a big difference in sound between this 2011 remaster and the "original" CD version. In fact the difference is quite surprising. This 2011 remaster gives a richer fuller sound with clearer vocals, making an already fantastic album even better. Queen II is one of the group's best albums and, with "Queen" and "Sheer Heart Attack", forms a triptych of their early (and best) music. Indeed, "Queen II" and "Sheer Heart Attack", although issued several months apart in 1974, form a sort of double album. "I do like to be beside the seaside" forms the playout groove of "Queen II" and plays us into the brilliant "Brighton Rock at the start of "Sheer Heart Attack".
Queen II is glam rock at its most amazing. Wildly over the top, and yet full of emotion and poetry. If you think "Bohemian Rhapsody" is Queen at their best (it appeared on a later album), then you'll find the operatic vocals, the heavy rock solos, the changes of tempo, and the moving ballads done much better on Queen II.
I bought the double CD version of the 2011 remaster though, overall, I would recommend the single CD version. The five tracks on the bonus CD are really not worth an extra £7. The BBC version of "Nevermore" is great - perhaps better than the album version - but the other tracks are also-rans strictly for the enthusiast.
So a brilliant remaster of one of their best albums, but stick to the single CD unless you are a real hardcore fan.