Not yet, because we are still waiting for Blesta to mature into a stable product with the features we need. (eNom module, migration path from AWBS.com, license management module, and a few critical features still missing.)
Once Blesta if fully mature and has the features we need, then we'll probably move all our brands and company's into it. This includes:
four hosting websites (two low-cost brands and two high-cost brands)
a domain-registration-only website, an ssl-sales-only website
three different PHP software applications (which will use the license management module)
a web design website (so invoice-only).
a VoIP sales/billing website
We're currently using a combination of AWBS.com, phpaudit.com, whmcs.com, and excel. Needless to say, we are very much looking forward to when we can eventually switch everything into a single installation of Blesta and (hopefully) use multi-company support to manage all the different websites from a single back-end location.