Found a BP2-V3 on Sale and bought one, the assembly is not hard at all. In use I have not noticed the rails or bottom part digging into my back, so the issue may not be present in the slightly smaller bag (or my back/strap usage is different than the previous poster). Happy with this bag so far for the price I paid ($69). It is better than the cheap MVP $30 one my son is now using. We will see how long it lasts...