I have a myler bit and love it. I spent the $20-$30 on a bit and it just never worked out. Vega would never listen to me, would run right through it, and it just turned into an ugly battle any time I got on her. I did quite a bit of research on the bits, and then quite a bit fore to decide which bit would suit her best.
I liked the design of it, how it's curved to go with the horse's mouth, and how there are 3 parts so it eliminated the nutcracker action.
Since i've used it with her, she's been a lot better. She does listen to me, and getting her to bend and lift up her shoulders have been so nice. And while she does gape a bit, its just mostly because she's not used to the bit. But i'm working on that with the pessoa system I have.
This is the one I have: http://www.toklat.com/dyn_prod.php?p=89-29045&k=88111
I got the low port because the other bits I have have no tongue relief and thought that was something she needed. Boy was I right. And it also looks very nice on her.
Another thing it has is copper inlay which helps with acceptance and softening.
If you have $200, i'd spend $80 on a really good bit.
Here's the Myler website for more information http://www.mylerbitsusa.com/