Permanent residency usually gets you most of the practical substance of citizenship. Typically that means the right to live in the country indefinitely, work for any employer without sponsorship, change jobs freely, run a business, access public healthcare and education on the same footing as citizens, and in many countries buy property and access social benefits. You stop living from renewal to renewal.
The usual gaps compared to citizens: no vote in national elections, no passport of that country, limited access to some government jobs, and, importantly, the status can still be lost. Long absences abroad, serious criminal convictions, or in rare cases fraud in the application can end PR, whereas citizenship is far harder to revoke.
Compared with temporary residence, the leap is security and independence, since your right to stay no longer hangs on an employer, a course, or a marriage. The exact benefit list is country-specific, so check the immigration authority's description of the status before assuming any particular entitlement.