Having owned Fortune Coilovers and having my MR2 be the car used to develop them for the SW20 platform, I can say... I love their products. Being able to drive to drop them off in the event of rebuild is a plus as well, but I had them developed for my R53 Mini Cooper S and my 93' MR2. However, if you're looking to get them for a Fiesta, would you buy the Mazda 2 500 series and select different rates and have them valved for those rates? I don't think they produce them for the FiST anymore.
That being said, B14's are also great and have raving reviews on here. I have a set that were on my car for a little bit, they are the Fiesta/Mazda2 version, but they rode and handled great, I just swapped to shocks/springs to raise the car a bit because even at their highest setting (that I felt comfortable setting in the front) they were still a little low for my girlfriend to drive with my Mountune Splitter.
Having damper adjustment and ride height independent from preload as well as camber plates for the front would give a nod to the Fortunes, but the price tag on the B14's is also very attractive. I'll be selling my B14's for pretty cheap soon, but they've been repainted and not the original color.
Can't go wrong with either to be honest, but I would love some Fortune's for my car.