I used it briefly. As the butt of a joke.
It always struck me as a cut-rate Sigil, but without much depth, without any significant reason as to why it hadn't been turned into a field of cinders by warring fiendish armies wanting to access what few portals it had, or destroyed by groups opposed to its mercane rulers (such as the Planar Trade Consortium and others).
It wasn't given enough depth to convince me of it having much inherent worth outside of 'It's [booming voice]EPIC!!11!!!!!![/booming voice] where the streets were cleaned by 50th level streetsweepers, you bought fish from 32nd level fishmongers, and the place was teeming with 21+ level Union Sentinals who rather than serving as deific proxies, or ruling empires or fighting for higher philosophical ideals, they instead were pulling a 9 to 5 arresting epic pickpockets in Union. Apparently the job market for epic level fighters was poor, so that was the best they could get.
It had too many flaws for me to take seriously, plus that it attempted to replicate many of Sigil's attractions, but without its context, depth, and living setting mechanic in The Lady of Pain to justify its continued existance.
If I were to ever actually use it, I'd have to seriously rework the place, and give it some hidden, behind the scenes backers: such as perhaps a proxy of a draconic deity of wealth, or an exiled archfiend, or even a cabal of titans to provide a bit more than mercanes and their uber level traffic cops protecting a city that looks more like uber level disneyland than a realistic planar metropolis.