Apartment Life: Butler vs. Servo Robot

In the Apartment Life expansion pack is a new NPC character, the Butler. He does many domestic chores, much like the Servo or Robot does for a family. So the question is: Which is best? Hiring a butler for a base fee of $20 and $25 per hour, or getting a Servo (Open for Business) to join the family?  First of all, it is more difficult to get a Servo. You can build up the Robotics badge and build one yourself, you can become friends with an existing one and invite him/her to move in, or you can go to another Sims’ store to buy one that they have built (and pay the specified price). The butler can just be hired over the phone. One disadvantage to the Butler is that he seems to arrive around 10 am and leave sometime in the late afternoon or early evening, while the Servo is a part of the family and is there all the time. The Servo is controllable, so you can tell him which chores to do, and he doesn’t need to sleep much. He also has fun and social needs, so he will not do chores all the time. But he may play with the kids or pets. The Butler will cook and serve food, while Servo will make food but not serve it. This means children won’t be able to eat until another family member serves it. The Butler can also order groceries or hire repairmen/exterminators when needed, which is very useful. I read that he will also greet guests that arrive. I believe both will clean and do the gardening. What are your thoughts as to which is better in which circumstances?