My decision would never involve leaving Starwood but whether it is worth continuing to actively pursue elite status. Most of my stays are in Sydney so maintaining status "on the cheap" is not really an option.
Sometimes I stay at a Starwood hotel when a comparable, or more convenient hotel is cheaper, to keep my stays up. If I get long term real benefits, I'll continue. If not, I'll probably play the field based on current pricing/promos and add a couple more cards to my (already bulging) wallet.
I've got multiple airline memberships, no real elite status, but financially it works well for me.