Currently using QB Sync (A must) and Client Portal. Its taken me sometime to get everything up and running but, so far I'm pretty satisfied. Client Portal currently only shows Past/Current Invoices and Past payments. It does show the client the details of the invoice if they click on it.
Its not the most impressive thing, but I'm told there will be an update in June that will overhaul the entire client portal. Implementing it is as simply as posting a link on your current website.