What are the best Room Accustic Treaments members have found?

GIK provides the lowest-cost treatments that are attractive and are developed and tested in accordance with known acoustic theory (unlike some of the gongs, pucks, tuning-fork like devices, etc.). They will send a treatment plan for a low fee, refundable with the first order. Their treatment plan will not skimp on devices, so you may not need all of what they suggest to meet your needs.

ASC and Vicoustic are also very good. The detail of workmanship tends to be a little better, but the cost is higher. Vicoustic stuff can be very stylish. Vicoustic offers an innovative tuned bass trap that can be adjusted to address any particular bass frequency that is problematic.

I would advise you to do some basic reading on room acoustics first, so you know what you are trying to accomplish (bass trapping, first-reflection attenuation, removal of slap echo...).

Most acoustics manufacturers use Guilford of Maine fabrics to cover the panels or traps. Guilford offers thousands of fabrics; by choosing one to go with your decor, you can improve appearance tremendously at relatively little incremental expense.

As you add treatments, be careful not to add too much absorption without some diffusion as well. Combination products, such as the GIK Alpha series or RPG's BAD panels or any ASC product, will give a more pleasing acoustic result, in my experience, than simply adding panels made with fiberglass, rockwool, or foam and without any reflective elements.