The best replacement for vtiger is sugarcrm.

The best alternatives to vtiger are rated as following:
★★★★★  sugarcrm
★★★  zoho
★★  salesforce
★★  openerp
★★  zoho crm
★  zurmo
★  dolibarr
★  dynamics crm
★  opencrx
★  x2crm
★  openbravo
  civicrm
  sugar crm

Your alternative for vtiger is not listed? Suggest!
Speaking about vtiger, one probably shouldn't forget about asterisk integration.

Other search terms related to vtiger and their ratings are:
★★★★★ asterisk integration
You have in mind a companion for vtiger and it is not yet here? Propose!



Google Trends

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vtiger
sugarcrm
zoho