The best part about using fidel is that it allows me access, through an api or web app (mobile) directly into my customers credit card account with just one click of their mouse! I have only used this feature once but so far i am very happy because everything was running smoothly when they say its smooth!! Not much at all really since you get what u pay for.
There isn't anything wrong in particular from experience yet if there were no cons then we couldn’t do without them lol :). We are solving our clients issue regarding PCI compliance by giving full control over cc info which helps us maintain data security as well.