What is the difference in APR between revolving credit and installment credit?

I recently transferred my remaining two credit card balances to a card with a balance transfer rate (APR) of 4.99%. I am paying off the card at the rate of $1000 a month. I should have the card paid off by the end of the year. A Lender called me today (I had paid off the lender) and said I should consider an "installment loan" with the lender at a higher rate (8%). She said my APR was "revolving credit" and she could offer me "installment credit" which was better, even at the higher rate. What's the difference in the two? Would I save any money with an installment loan?