Hi Erpini,
I'm currently a pilot in the Dallas area and whilst I did not do my training at Monarch and actually have not been into the school itself, I have had some contact.
Firstly, Dallas is a great place to flight train, especially the Addison airport where Monarch is located. Addison is a really busy little airport with lots of flight training being conducted and a fair amount of corporate aviation also. It is also located in the DFW class B and makes for a good training environment with two local busy airports keeping you on your toes (KDAL and KDFW).
Now to Monarch itself, like i mentioned, i have not personally done any training there. However, I work for a small company out of KDAL and 2 of our 4 pilots were flight instructors there. The first has been with our company for a few years coming straight from Monarch as an instructor, he is a GREAT pilot and instructor and only has the best things to say about the place. The second guy i work with was a senior instructor there up until recently and again a top guy and great pilot. My mentioning these two pilots is meant to emphasize the quality of Monarchs instructing and production of good pilots/people.
From the many stories my colleagues have told me about their work there, it seems that the school is friendly, a great place to work and learn. I believe it is run by an ex-airline captain who apparently does a superb job.
Again, i stress, i have not even so much as been there myself but i have heard very good stories (i therefore can't comment on their pricing either).
If you need to know any particulars about the school then the guys i work with are only a phone call away and still are very much involved with it, so let me know.
Jez