The new Coleman Extreme series are good, we have a 45ltr version, block ice in ambient 30c (on our latest camping trip) lasted 4 days...note it was block ice.
The teenage daughter was into the drinks constantly, and typically did'nt close the lid properly all the time, kept it open to stare at the drinks and hope they would jump into her hand.
I tried the party ice, 2 days max in the same temp conditions.
The price, $145.00, a winter sale at BCF, a good overall product, you can pick them up from any camping outdoor store.
I wanted a Eva kool, but the finance minister would'nt come at that...I'm happy with this purchase, good value for money.