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You probably won't find a lot of input here based on similar questions that were raised in the past about various providers.  As you may already be aware, Ace is only authorized for hosting QB but they promote unofficial hosting solutions for Lacerte and ProSeries, like many of their competitors.  If you run into problems, however, Intuit will not be able to support you to diagnose the issue and come up with resolutions.

The only official hosting solution that is available now for Lacerete is with Right Networks.  You can read more about this here: https://proconnect.intuit.com/desktop-hosting/

I have been using cloud-hosted Lacerte for my business for quite a time now and never experienced any major issue since then. Their overall cloud services are pretty good compared to others in the market, like downtime (occurred only once till now, when they upgraded Windows Server from 2013 to latest one), then they usually respond on time. I host Lacerte with QuickBooks and SmartVault and happy with Ace Cloud Hosting services.