I don't have experience with them, but for reliability and long range touring many seem to prefer the Surly Long Haul Trucker frame.

As a side note on building a bike: I could easily build up a bike myself, having 20+ years as a bike mechanic and service manager, but chose a bike that met 90% of my needs - a Novara Randonee. I bought it during 20% off sale, only changed pedals, saddle and stem/bars. I am very happy with it, have had not a single problem. The rack on it is particularly strong, tires rugged, gear range excellent and the parts easily obtainable for replacement. I spent the time I would have on building a bike riding instead and the money I saved on touring gear.