I have owned an Adona Zero SR4 for about 15 years, and I love mine and recommend it. The price is fair, they look good, and most importantly, they are infinitely adjustable. The granite shelves as you probably know are laminated to MDF underneath with a layer of damping elastomer, and I think it is really effective sonically.
I think that the customer service was fine, but I do wonder if they have, or had some influence with Audiogon as advertisers, because I did a positive review of the rack way back then, and only mentioned that there were no instructions for assembly, and the review was rejected by Audiogon.