Migration from Reckon Accounts Hosted (QuickBooks engine) to Zoho Books

Migration from Reckon Accounts Hosted (QuickBooks engine) to Zoho Books

Hi Everyone 

I want to move to Zoho Finance from Reckon Accounts Hosted as I have a lot of other things happening in Zoho One and it seems crazy not moving. 
(Reckon has a QuickBooks back end)

I really would like to extract all the data from Reckon, especially ALL Transaction & Banking etc details for the last 2.5 years.
So I can accurately show ALL the purchasing history of each customer. 

From what I can see most of the data is available to be exported from Reckon in an Excel format - Except the detailed transactions - that are in a flat file and look like they need a lot of work to tidy up.  We had some difficulty getting the exporting to work and were not 100% sure we had everything.  

Questions I have please
1) Has anyone had any experience in doing this with Reckon Accounts Hosted? 

2) Am I best to go this direction (Export & import) and then run 2 distinct systems in parallel for a few months until we have confirmed everything is accurate in Books before we shut down Reckon?
Or
Am I best to use the API and connect Reckon with Books so the data is replicated? 
Is this how the API could work for us?
Can I work in both apps and share the data live? 
What are the limitations you can see or have experienced?
If this did work - when we close the Reckon account and end the subscription will all the data stay in Books? 
 
This is the API info - I get the impression this is not as simple as the QB Online 
(
Intuit QuickBooks® Desktop SDK v6.1 / qbXML / Intuit QuickBooks®  
web connector v2.1.0.30 plus RESTful API v2.1)

As much as Zoho have said they can help, I am struggling to get real and assistance that will allow me to understand and make it happen 

Looking forward to any help you can offer