Hi... I have tried it out but I wasnt really into it. I like the result best when I first blow dry my hair with a brush like this:

and then afterwards use a roundbrush for the finish. I also have a hair straigthening iron but it takes a bit too long for my personal taste ... To work with roundbrush requires a bit of technique but I think the results are just as good! I suppose a good brush is essential: I use this brush for blowdrying myhair straight:

Also a tip: I think what really makes the trick (no matter if iron or brush) is to let the hair cool down long enough- because only when the hair is really cooled it remains straight - if you stop the hairdo when the hair is still warm or even hot- there is a great possibility that it might frizz again!
Also important- good products to prepare the hair: I personally use L'Oreak Kérastase Oleo, but I know that Tigi or Redken also make great products! :-)