I"m going to say both are nice but the status is a lot more important.

Having status gives me something nice with every night: upgrades, free drinks, breakfast and other small perks.

The free nights are nice, but I'm probably only going to get a week or so free a year and usually at only standard rooms. And at least at IHG hotels the stays are treated different on rewards.

At the end of the day having a lot of really nice stays is better than having one free week of just good stays.