There are two kinds of raises, normal and full. The normal raise has the penalty that it lowers your constitution by one point, the full raise has no penalty (assuming, of course that it succeeds). Neither raise affects your ability to make level in any way.
However, you need to understand how leveling works when you are comparing the advancement of two characters. There is no 'experience' counter in the game. Each time your character kills (or is hit) by a monster he has a chance to make level. The probability is based on your character's class, race, level, the level of the monster and the level of the dungeon. If two characters are the same race and class then the fact that one seems to be advancing faster is just the luck of the draw. Note also, that the Ranger class is the hardest class to level.