Will Hubspot connect well with variety of accounting softwares?

Hubspot has API hooks that you can access third-party accounts through HubSpot. I would look into solution partners and see if there is a ready-made app that can give you what you require. I don't think to build it from the ground up would be worth the effort unless: 1. It is mission-critical 2 You cannot customize Hubspot to accept an import from another application in the manner that is acceptable to you 3. That is your business, building apps to share with the HubSpot community I would need to know more about your operation before I could guide you to a better decision.

Check the marketplace, if not you should be able to connect via an API connection.

We have not connected ours but the HubSpot Marketplace is a good place to look. I saw a couple that had some basic native connections such as Freshbooks and Xero and PieSync and Zapier offer a more robust connection for a fee. I would love to see a robust native connection between HubSpot and Quickbooks Online.

It depends of ERP software. In the marketplace you will find severals software that have native integration. If your actual ERP doesn't appears in list, you have 2 choices: 1) Conect them using API's: I have conected, with languague programming, actions that I need to track. It's not very hard. 2) Zapier: Hubspot have a native conection with Zapier. You can work with it to attach all systems you need to work.