A neophyte with SICP

I bought a used copy of the first edition of SICP. It wasn't much cheaper than a new copy of the second edition, but it arrived in one week, when a new copy would arrive only in 6 weeks.

So, should I be aware of any notable differences between the two editions?

http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-6.html#%_chap_Temp_3