Randy,
I owned a large rack system of multiple racks of Adona AV45 going back to 2003 & 4 with very good results. The AV45 racks can be assembled in many different variations/configurations and i've had alot of them between my old 7.1 & 2 ch hybrid system that I had in CT from 2003-2007 and then moved to other homes I've had in SC prior to me selling off all the HT/multimedia components and speakers in 2008-2009. The flexibility of Adona allowed to treat is as an "audio erector set" if you will and rebuild into many different rack configurations from 2009 until last years in several different homes and system configurations. If you look back at my virtual system and scroll down, you can see a sampling of photos that show the systems while also seeing a few of the rack configurations I was able to build out of all the parts.
Adona AV45 (and his other racks) have varying levels (as you go up the model list) of use of sound constrained layer damping techniques both in the multi-layer platforms as well as the use of different materials in the racks themselves. These CLD techniques help capture and channel vibration away from the gear.
Many of us have also found that supplemental use of higher-end footers, fine-tuned additional platforms and/or or damping platforms helps refine the performance even further. Roxy, Mike L and others all have long experience with Adona as do both myself and 9 other people I know who either have a newer line (ERIS) or the AV45 line with a heavy emphasis for those who have bought in the last 5 years of adopting the ERIS models. There an additional 2 who have gone with the Zero GX and the level that replaces it (Altaira). Others like Mike L have the top model, the Zero GXT for their most important turntables and related components.
After 19 years with the AV45 racks, I decided last year to begin the process of swapping out my AV45 one rack at a time and moving to the Zero GX (has 3" columns while the Zero GXT has 4", both have slightly different aspects to them). From what Paul tells me the Zero GX has been replaced by the Altair for both design and supply chain reasons (the Altair is the next-gen design). I finished the Zero GX upgrade with the last rack section early this year.
I was alway very happy with both the flexibility, price, overall value, function and look of the AV45 gear. The Zero GX performs and looks even better and I an extremely happy. The fit and finish of the Zero racks and other new models is even better and in the case of the Zero GX I was able to hear an even better sonic result in imaging performance and other aspects.
The great thing about Adona is that the multi-element platforms will hold any weight component I've had on them from 15 lbs to 150 lbs (and I'm told others put more on them). The platforms are the same for all Adona racks and can be made into custom sizes in addition to the stock 18x18 (inch) and 19x24, 19x,21 stock sizes. You can by the platforms with your first rack once and then use them over many different Adona rack models.
The Zero and his latest models are a meaningful improvement; the AV45 however is nonetheless still a great performer for the money.
There are higher cost, more sophisticated (i.e. more detailed tech and designs), even more beautiful and fancier racks and platforms out there. Some of have limitations in terms of configurability, movement of shelves after initial build at time of purchase, etc... there are several major names on the "uber racks" list that frankly I think are great options from US, UK, Europe, South Korea. All are excellent. All have one thing in common,....the uber rack options are all extremely, and sometimes outrageously expensive. They will also take months to build and deliver and while frankly Adona builds at time of order and this can range from 2-8 weeks in my experience depending size of order, materials supply, previously in queue how they are still much faster than the 4-6 month timeframes and less costly than the uber options I looked at both in 2002-3 and over the last couple of years.
Adona gets the job done and at a fair price. The direct-sale model helps with the economics too for obvious reasons.
You can pay multiple time more and get more or different or better in some way but honestly, I cannot justify the $75K-$100K+ (or more) that it would take in 3 different other manufacturers rack and platform systems based on quotes I have procured to try to do what I need with my 3 favorite uber-rack manufacturers.
There many, many options out there as well for alternate solutions at the same price points as Adona, many available in all countries, some not available outside of Asia or Europe or Eastern Europe (or other areas) that also great options.
For me, it's Adona for over 20 years and for the foreseeable future.
YMMV and IMHO and ll that :-)