How long to stay in......

Kauai vs Maui... we def want to go to these 2 islands... I was originally going to do 4 nights kauai and 6 night in maui.. but i'm afraid due to traveling, we'll lose the 1st day pretty much out of kauai and then only hve 3 days left... being there is more to do in maui.. so i hear... i'm afraid to do 5 & 5....taking a day away from maui. Anyone been to both of these island??? What did you do???

As far as hotels... We're thinking Hyatt in Kauai and eithr Hyatt, Four Seasons or Fairmont in Maui.... which would you suggest???

Thanks!