[billyg]

I own an Eastman AR605Ce. During the time I was considering purchasing that guitar (early 2017), I was fortunate to visit a retail store that had several Eastman arch top models in stock, ranging from the AR372 through various configurations of the 400, 500, 600, and 800 series. I don't recall them having a 900 series. So, I A,B'd for almost 90 minutes.
My impressions were that they were all good instruments. The 400 series was the least impressive. The 800 was noticeably the best (but also considerably higher). The two I ended up comparing the most were the AR372 and the 600 series. The 372 and the 600 were significantly different and I ultimately settled on the 600 series as the sound I wanted to pursue. Again, both were good, but they were, not surprisingly, going for different sounds.
While the 372 series was going in its specific tonal direction, I personally treated the 400, 500, 600, and 800 series as all going for a similar sound or feel. The 500 series peaked my interest considerably, but I noticed enough difference between it and the 600 series that I set it aside in favor of the 600. Honestly, if I had only the 800 series to compare to the 500 series, I don't think I would have determined that the sound difference justified the price jump for me at that time. While the 600 series was enough of a sound difference (and I stress difference) with a much smaller price jump. I do believe the solid back and sides vs. the laminated back and sides made a tonal difference for me that day.
Hope this helps. I am not that well-versed in great arch tops, but I think Eastman makes good instruments and are generally good enough that we don't need to add the "for the money" moniker. They are just good instruments.