Pros: There are many pros to working with a partner when it comes to lifting weight. The first benefit is the motivation factor. A partner is a great motivational tool. People that usually workout with partners tend to go beyond the limits that they set for themselves. The partner usually pushes them to go further. Another pro of working out with a partner is that you will always have a spotter. It is hard trying to find people to give you a spot when you are working out on your heavy days. With a training partner, you will not have this problem. Your partner usually knows what you can and what you can not lift, so he knows when to come in at the right time. Another plus about having a partner is that they can tell you when you are doing something wrong. A partner can guide you in the right direction when your form is particularly straight.
Cons: Even though working with a partner can be great, it also has its down sides. One negative to working out with a partner is what I call the social factor. Many people have their friend or a group of friends workout with them, with the expectation of the partners being there to motivate them. These usually turn into social gatherings, where everything is done but working out. They talk about sports, girls, and anything else that has nothing to do with training.
Here is the rule of thumb when working out with a partner. You are there to train, not to find out what is the latest on your favorite sports team. Work out first and then talk to your friends. Another con to working with a partner is that sometimes the partners do not show up on time. If you want a consistent workout, you need to have a partner that will arrive at the scheduled time that you all have agreed upon. This make the workouts go smoother.