Free Sugar/Vtiger/VTE Comparison - Customer Support and Marketing tools

Customer Support tools	VTECRM	VTIGER	SUGAR
Tickets/Cases module	yes	yes	yes
Customer Portal	yes	yes	no
Bugs module	no	no	yes
Timecards module	yes	no	no
Asset module	yes	yes	no
Service contracts module	yes	yes	no
Trouble-ticketing tool (chat between CRM and Customer Portal)	yes	yes	no
Service Level Agreement timings	yes	no	no
Tickets acquisition by Customer Portal and email conversion	yes	yes	no
Shortcut between product rows and assets/service contracts	yes	no	no
Tracking of service used units by related tickets	yes	yes	no
Tracking of service used units by related timecards	yes	no	no

The post-sales management is quite relevant because we need to keep the customers satisfied after all the efforts we made to acquire them. VTE and Vtiger provide a complete support area but Sugar has only a few modules.
In VTE and Vtiger I find Tickets, Assets, Service Contracts; Timecards (a deeper level of Ticket) is available in VTE only. In Sugar I find Tickets and Bugs, but no one of the following features.
Customer Portal: a reserved area where customers can open new requests and share documents, directly communicating with the company via trouble-ticketing (a sort of chat).
Email-to-ticket: both Vtiger and VTE allow the conversion of email accounts into tickets.
Tracking of units: I keep track of the usage of a contract (for example the progress of a technical assistance) through Tickets and usage units. The same with Timecards in VTE (more timecards add up in one ticket).
Service Level Agreement timing: only VTE manages it, it's very important in order to provide an effective support service.
Another little trick which VTE offers is the shortcut between product rows (on Sales Order) and the related Asset/Service Contract.

Marketing tools	VTECRM	VTIGER	SUGAR
Campaigns module	yes	yes	yes
Newsletters module	yes	no	no
Target/Target list module	yes	no	yes
Recipients lists based on filters (accounts, contacts, leads...)	yes	yes	yes
ROI tool	no	no	yes
Newsletter sending and scheduling	yes	no	yes
Post-sending statistics (received, opened, clicked, unsubscribed…)	yes	no	yes
Statistic summary per recipient	yes	no	no
Newsletter templates (editor, HTML, variables)	yes	no	yes
Fax module	yes	no	no
Sms module	yes	no	no

VTE and Sugar provide more marketing features than Vtiger. The latter allows to create generic Campaigns with recipients list, but not Newsletters. In VTE and Sugar I have the possibility to send (or schedule) Newsletters (even if only VTE has a specific module), read the statistics and, of course, create newsletter templates with variables (strings of code automatically replaced by CRM content: for example, the Contact's name or the unsubscription link).
Only Sugar provides a nice ROI tool about campaigns, while VTE provides the statistic history per recipient (Contacts, Leads…).
In VTE also Fax and Sms campaigns are possible, by configuring these services

Read all the comparison work about Sugar/Vtiger/VTE free edition 

The comparison work is based on

SUGAR 6.5 COMMUNITY
VTIGER FREE 6.3
VTECRM COMMUNITY 15.05
All three the versions are free and downloadable from their official sites.