Teamweek is a cool project management service founded in 2013 and built around timeline/Gantt chart view. Teamweek reviews praise how simple it is, and the pricing policy (5 users free, $71 for 19 users) is very SMB friendly. Teamweek clearly targets small organizations, staying away from complicated 'hard core' project management features. If you are looking for a free Teamweek alterative, require open source code access, want to have a choice between cloud and on-premise (self-hosted) deployment, need client management and invoicing tools, take a look at Bitrix24.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.