More or less, although it would still be wise to travel with your COPR until you receive your card. Canadian visa officials will not deny re-entry to a permanent resident, but for those from visa-requiring countries there may be problems booking commercial travel, since ordinarily airlines require a PR card or a valid visa to issue a ticket. (They're on the hook for anyone who is turned away at the border.)
Alas, this is out-of-date information. Citizenship eligibility rules changed earlier this year, so that
four years' residency (out of the previous six) on permanent status is now required, with no partial credit for temporary status.
If you do not travel outside of Canada, you will be eligible to apply for citizenship in July, 2019.
These requirements may or may not remain the same pending the outcome of October's elections. These changes were wrapped up in a relatively controversial citizenship bill last year, and if one of the opposition parties forms government this fall they may seek to revise these rules.
