We have been using the term "brand new" as a way to show that we're trying to approach the domain industry a bit differently than our 5-10 year old competitors. I think the biggest example is that we've open sourced our javascript frontend (http://github.com/badger/frontend) which exclusively uses our API (http://badger.github.com/). We think the domain industry is ripe for disruption and we think we have the right team and ideas to execute.
As you pointed out though we don't have a proven track record. Unfortunately, there's not a lot we can do about that. Service guarantees and long-term contracts might seem nice on the surface but wouldn't really change much if we went out of business. I believe the quote goes something like: "The only two things guaranteed in life are death and taxes. (Benjamin Franklin)"
That said, we're a startup in San Francisco with an office and employees and have been around for over a year. We previously were a domain reseller (rhinonames.com) but have spent the last six months becoming ICANN accredited and building badger.com. We think we can build the best registrar around and we're here to stay.