This Dungeons and Dragons modified system uses a point buy system for character abilities rather than the standard class advancement system. This mod was written to leverage the existing Dungeons and Dragons rulesets and infrastructure while allowing players greater flexability in character creation and increasing the realism of character advancement. It still relies heavily on hit die, but the rules for D&D are very heavily dependent on character hit die and so it would be very difficult to create a truely levelless roleplaying system that leverages existing D&D infrastructure.
The effects of applying these rules have been calculated and tested to be as balanced as the existing D&D system, or as close as possible. In other words for most character types if you were to take two characters of equivelent level in the standard rules and convert them to the point buy system they would have used roughly the same number of points Prestige classes are somewhat of an exception in that they generally lead to faster ability advancement and are generally not as thuroughly balanced as the core classes tend to be. The provided rules for training can be a means for the DM to allow characters to have the more rapid type of advancement associated with being a character of prestige.