You will get all the Enterprise features for CloudExtend Excel for NetSuite during your trial period. After your trial period is complete, you have an option to subscribe to Enterprise Edition and continue using those features or subscribe to Personal Edition with subset of features.
Trial period has a limitation on the number of records that can be uploaded at a time. Currently you can upload only 50 records at a time. You can always select another set of 50 records and continue the upload process.
You cannot move between Production & Sandbox accounts during trial period. Your access is restricted to the environment you selected while signing up for trial.