About as barebones as they can get away with. It "signs" documents, and that's about it. You manually enter where things get signed and hope the UI allows you to actually navigate and do the correct actions. Self signing your own documents is apparently non-existent, even though the feature was selected, and signing documents while building it was buggy at best.
SignHouse offers one thing acceptably: you can simply sign a document uploaded and have an audit log (and the audit log is actually useful). But if you need ANYTHING more advanced, I recommend going with one of the larger companies (PandaDoc is my personal favorite, though I think their pricing is too expensive).
One big concern with SignHouse (back when I was just researching the service): nothing real seems to exist about them outside of their own articles (and they seem to have 100's). It's tacky, fake, and I'm fairly certain AI generated (or from a hired firm).
To other devs out there looking to get into this space: just make a solid product and share some access to everyday users. Make it stable, offer the features they're looking for, and don't charge prices out the nose. Maybe have it a two tier system (# of documents per month per user) sort of pricing. But don't be sleazy, and make sure your product works before trying to funnel users into jumping in early with lifetime deals with the promise that the product will improve.
Shipper.now