For miniatures, it is going to be hard to beat Myler driving bits(many of the other better makers simply don't make bits in sizes to fit miniatures...). I just don't know about the Myler 'knockoffs'; have seen pics of one that broke, and it looked very poorly made-out of thin and insubstantial material, with resulting SHARP edges....they may be fine, they may not? I have seen them for as low as under $20, and for around $40---have no idea if those're the 'same' bits, or whether there is more than one producer of the knockoffs? I need a bit for my 38" mare-she had liked each one I've tried better than the last, but still isn't 100% happy, so I've been closely observing her responses, and studying bit types, and have decided to order her a Myler(and have been saving up toward it!) with a particular mouthpiece. I have two Mylers, bought some years ago at AMHA Nationals, for a discount(available NO MORE; the other dealers made sure of that after that year....
They are the Comfort snaffle and the E 32 Mullen w/ barrel--and they are the two best choices I could have made,getting 'only' two!--the first is perfect for the beginner driving horses, after they learn to accept a bit by carrying the eggbutt; the second has worked very well on EVERY horse I have that drives(but of course, isn't wide enough for the bigger mare!)
A friend who ordered the Myler book and DVD loaned it to me; so far, I've only read the book, but the philosophy is very interesting and definitely 'food for thought'. Kind of opposite to what you might have thought, IMO....
I will say that the more I learn, the less enthusiasm I have for 'standard' single link broken mouthpieces. The ones that 'come with' most harness should be tossed, IMO-they have big, coarse, joints in the middle, and where the mouthpiece joins the cheekpieces is likely to pinch, on all of that type I've seen...I do have some that are made much better, and the horses seem 'OK' with those, but one wonders how much better they might be w/ something else? ( I would LOVE to own a whole 'collection' of Mylers, but they are so pricey, it is hard(for me, at least!) to afford a 'selection' of them....would if I could, though!)
A properly chosen Myler would definitely be my recommendation. If getting something else, then I'd look for: non-pinch cheeks, well-made and sturdy but refined 'jointing', if either a single link OR a true french link, and NO solid copper mouthpieces(copper may be TOO acidic, and is too soft; it will become abraded and worn, and/or have sharp edges, in many cases--this I know from experience!) Sweet iron is a great mouthpiece material, but I have yet to see it available in miniature horse bits, so stainless is next best. Because I have a catalog, I do know that Ozark Mt.(in addition to Estate) also carries some genuine Myler bits; other suppliers of mini tack may, also. You probably won't find any price breaks(at least, I surely haven't, and I've been LOOKING!), but I like to do business w/ those who have shown themselves to be 'friends' of the Forum and the Rescue....and will, if I can.
Margo