We're hosted in live replication server facilities on both the East and West Coast of the United States. Heroku, the server platform we use, backups constantly to Amazon's s3 servers. We also run our own independent, external backups. At any time you can export your customer and invoice lists and you can live backup tickets and invoices to Dropbox or Google Drive for additional backup protection.
Here's our track record on uptime:
Also, when you sign up we state our commitment to open sourcing the software or giving it to the community or an individual to run if we are not able to to ensure that the community can continue using the system in the future.
If you have any further questions, just write us at firstname.lastname@example.org!