Let's start with economics and forget the diminishing returns. There's a mint Ref 40 on A'gon for $11.9K and a 5SE for $10.5K. That Ref 40 is $10K less than I paid on a discounted basis less than 1 year ago. I haven't heard the 5SE, but the Ref 40 sounds amazing, it's got a whole lot of extra build quality than the 5SE and it will sound like it. Sell the kids, mortgage the house, take the wife out to dinner and promise her anything. Buy it if you can come close to affording it in the next 3 years. You'll own it forever and won't get a better deal than that in the next 3 years. Seller is giving it away. Wait till you hear it!