get both, they both are free.
DURING INTERVIEW when IO asked for my tax returns,
i gave the IO my account transcript only. originally when i submitted my forms i included my w2 as well.
i asked if they wanted w2 as well, IO said NO.
guess it depends from IO to IO as what they want. i was prepared and had all 3 ( account transcript, return transcript and w2's of all the years)
from my first experience i learned. you never know what they might ask or want. so better be prepared for the worst.