I have a yeti that I use for work and it does great. They are heavy and expensive but keep ice longer than any other.
There are ways to help keep ice longer in conventional coolers. Freeze/cool before using. Use block ice rather than crushed. Add dry ice with lots of newspaper on top. Keep the cooler in the shade at all times and keep the lid closed.
Three to five days should be no problem with any cooler. I use the Yeti on eight day trips in 80-100 degree temps.
