I am currently updating the treatments in my listening area where both SQ and aesthetics are major considerations. I started with REW measurements to establish a baseline and be able to quantify the impacts of the treatments. This required a minimal investment for a calibrated mic and cable and not nearly as daunting as it initially appears. I actually sent these measurements along with pics and layouts to both GIK and Audio Advice to help in their free recommendations.
GIK came back with an extensive plan with a mix of treatments that I have partially implemented with their 4" Impression panels. A few issues but overall quite happy with the aesthetics of the panels. Don't really care for the look of the GIK pure absorption panels so I wound up purchasing Tonnen panels off Amazon for the first reflection points. The dimensions of the Tonnen panels were also a better fit for my space.
Audio Advice handles Vicoustic products, which are some of the best looking products (also more $'s) but their advice/follow-up was very poor compared to GIK so I stopped working with them.
Thus far the benefits are obvious in both the REW measurements and in listening. I am still debating whether to treat the ceiling, if I do, I will likely use a combination for the Vicoustic absorption and diffusion panels for both performance and aesthetics. I am fortunate that I don't have a major need for bass traps.
As someone noted, doing this in stages makes a lot of sense starting clearly with the first reflection points. The law of diminishing return applies.
FWIW I was shocked at your shipping cost. I paid $124 to ship 140lbs of GIK panels from Atlanta to Cincinnati!
Best of luck...