Why Mat or Reformer Class?
So many clients have asked “why do mat? Isn’t reformer better?”
Some believe that mat Pilates is like yoga.  I can tell you that it is not!
Both reformer Pilates and mat Pilates are equally as challenging but in different ways.
The reformer provides support for clients while working out.  As you advance, the reformer workout is about removing that stability so the exercises are more just hands and feet on the carriage or foot bar.  By removing stability, you as the client, have to create that stability for yourself using your core muscles.
Mat Pilates starts with more stability, having more of your body supported ie laying on the mat.  Then, there’s a process of taking away stability to challenge your core.  It can be really hard work for the non moving part of the body to retain stability whilst also focusing on moving parts of our body. Essentially, during Mat class, you challenge your workout by focusing more on the “non moving” part of your body to build strength through resistance to movement.
So, Mat Pilates or Reformer Pilates?  Often clients have a preference for one or the other but many do both!   
Either will get you to your goals.