I use an "indian hackamore/bosal" on Lacey. She really likes it, but I agree with JDI and smrobs, it depends on the horse for sure.
Mine attaches to your headstall where you'd attach a bit so it actually ends up being really cheap, since you're only buying the noseband. I got it for about $15 on ebay
The only complaint I have with my bitless contraption is that it's difficult to direct rein in. Direct reining can happen, it's not impossible, it's just more difficult, imo. However, that has forced me to work on my neckreining skills which is good.