Get a frame relay or T1 or frac-t1. More reliable and the telephone company gives it MUCH higher priority when it comes to repair.
DSL is NOT a business class service, despite it being sold as such. It is useful to a business only if they do not depend on their internet service being up all the time.
If the DSL goes down, will you be frantic trying to get it fixed, or will you be one who allows the provider to get it fixed as quickly as they can without hounding them every hour? The answer to that will determine whether DSL is right for your business or if you need something more reliable. The lower speed per dollar of a frame relay or T1 goes to paying for the priority given to it by the provider. A high speed DSL isn't worth much if it's down, no matter how low the cost.
NO DSL provider is going to be able to provide you with true business class service. You'll always have to deal with the possibility of waiting a full day for a repair dispatch, or many days if the telco has to get involved and has to do a major repair.
I can't say for sure that anybody is 'better' than Covad. Covad does have their downsides, but a lot of that is due to the nature of the product they sell and the providers they have to deal with. They do have some customer support problems that they can't seem to get resolved, to the degree that my department doesn't like having to deal with them and a good portion of our day is spent doing it just to get minor things taken care of. Northpoint is worse in many ways as far as repair time and dealing with their customer support, but again, they're only selling DSL. There are a couple more providers, but I don't remember the names and I have never dealt with them.
Getting DSL directly from the telephone company eliminates one step in the support process though, so you may consider that.
But again, a reliable and higher priority service like frame relay or T1 would be highly suggested. We've had to fight to get our sales people to even consider selling something other than DSL these days, because DSL is an easy sell for them, which means a quick commission (DSL=supposedly high speed and low cost, easy sell).