Efficient Data Transfers

My company has approximately 8 satellite locations. Each location has data that needs to be uploaded to our corporate office on a daily basis. We need these transfers to take place as close to realtime as possible. We use a bonded T line (300K) at corporate office and DSL or Cable connections at satellite offices. The daily data sizes are 300mb to 2gb. We use PeerSync software to handle transfers. I would love to hear some second opinions on the most efficient way to retrieve this data from a remote site.