After several years with one billing software, and seeing MB in action, I thought MB would be a good move - so I waited until the new version was released. Version 5 was "released" a while ago, but it does not yet work as advertised. Its new interface is not easy to use. It's nonintuitive, even counterintuitive in some places. While I understand that they've rewritten the codebase from scratch, and that's always a monumental task, they still dropped the ball. I bought an owned unlimited license in anticipation of things settling out
MB may improve in a few years' time to where it's actually worth the money that they're asking. However, they've lost me as a client for good. I'll still use it for those clients whom I rarely bill, or bill only infrequently; and who usually pay offline anyway (freelance document production, technical writing gigs, the occasional proofing/editing client, corporate clients). I own the license, certain things about it work acceptably, I may as well use it when it won't be seen by anyone but myself and perhaps a few other admins. But put it out where people can see it and potentially get the idea that it's a good package to use? Put myself in a position where I'll have to keep paying money to keep getting the upgrades? Forget it. At this point, it's throwing good money after bad. The version I'm "running" is crippled, but not ready to be shot. Just put out to pasture...
I spent five months evaluating another billing system: hanging around its support forums, asking questions, downloading the trial version, and finally leasing a one-month license when I was 98% sure that I'd found a winner. I've got it installed, and now just need to customize and integrate, then switch my clients over. I'll wait until I've hit six months' use with this particular package, then sing its praises when I can do a good job at it