The best replacement for owa is piwik.

The best alternatives to owa are rated as following:
★★★★★  piwik
★★★★  oma
★★★  outlook anywhere
★★★  outlook 2010
★★★  activesync
★★★  owa light
★★  ews
★★  outlook client
★★  outlook 2007
★  bes

Your alternative for owa is not listed? Suggest!
Speaking about owa, one probably shouldn't forget about isa.

Other search terms related to owa and their ratings are:
★★★★★ isa
★★★ thunderbird
★★★ activesync
★★ tmg
★ isa 2004
You have in mind a companion for owa and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of owa in all years. Click on graph for more.
owa
piwik
oma