What is the price you are welling to pay for this and what is your disk space and bandwidth?
managed or unmanaged.
GS RichCopy 360 Enterprise - Voted #1 for data migration and replication in terms of performance and features. Replicate data across between servers in the same network, WAS, or even across the internet
If your website gets any traffic to speak of, you'll move a lot more than 20mb/day.
Tektonic has a plan that meets your requirements. I'm a new customer on a much smaller unmanaged plan but I'm very happy with the performance and support so far. I had a problem setting up my account and it was fixed within minutes of submitting a ticket.
I Currently have around 100 uniqe visitors a day. And I will be downloading all the properties in one file that will be around 11-12GB.
You really won't need anything close to 2GB ram for that. Those visitors can be handled by a VPS with 128mb ram if need be, and downloading those properties in one file will probably take quite a bit of CPU, but not that much ram (probably 100-300mb at most)
If you get yourself a VPS with 512mb guaranteed ram (and optionally some burst ram for peak usage), you should be fine.
If you really need 2GB ram, you should get a dedicated server.