Looked at some sunrise spas tonite and apparently they are metal framed. Didn't know this was something I needed to think about (and maybe I don't) but the guy made a big deal out of it. I can't say as I know what the others we've seen are (Artesian/South Seas, Four Winds, Viking and Catalina). Does it matter? I can see how wood rots and all but I'm not sure in the grand scheme this is a deal breaker criteria but what do I know.