In my continued search for/at used spas, I recently came across a used 2004 Reward. I'm also looking at a 2008 Reward. What significant differences would there be, structurally, quality, insulation/energy efficiency, features, etc., between these two year models. I can obviously see that the 2004 is a wood cabinet - is that an issue? The 2004 has a new ozonator and cover. The 2004 is $1500 cheaper. Assuming I have a hot tub tech go over both and there are no outstanding issues - what is a better deal, a 2004 Reward for $2,200, or a 2008 for $3,700? I'm sure this is a shades of gray question as opposed to black and white, but opinions from folks with experience with either of these tubs would be greatly appreciated!