Ask HN: Cloud Open Source vs. Saas for a startup?

Trying to decide between using all cloud apps or open source:

option 1 (all cloud):

- AWS (Our app )

- CMS Wordpress.com

- Email/Doc Management (Google)

- Accouting (Xero)

- CRM (Solve360 CRM/Highrise CRM)

or option 2(open source):

- AWS (app/wordpress/roundcube/owncloud + civicrm/sugarcrm)

- Accouting - offline (quickbooks/GNUCash)

Or a hybrid (which it seems like what most people do). What do you think and what is your experience?