I would try the openerp-magento-connector option because it has good documentation. I think both are proben tools that will do the job, if I were you I would give both a try, see how it goes and then use the tool. At the end of the day, the tool you feel more comfortable with, is the tool of choice

You can also look at Magento openerp connector provider by webkul : https://store.webkul.com/Magento-Extensions/Magento-OpenERP-Bridge.html

you can read reviews about them here :  http://www.magentocommerce.com/magento-connect/openerp-bridge.html