Both are great choices for your first arranger!!

My take... Like the ever flowing river of technology, at some point, you have to dive in!

PSR-970 - Newest... Lot's of features from Tyros 4 & 5.
Pa900 - Older... Light weight.

Again, both are worthy!
_________________________
~Johnathan
"The Shueys"
www.shueymusic.com
Yamaha Genos - RCF M20x - RCF HD10A (Stereo) - Jupiter Pocket Trumpet - Sennheiser e935 - Neumann KMS-104 plus-N