I think if you do a search there'll be lots of threads similar to this.
I think the difficulty is that most people here will have one or the other, and not both, and is therefore not really a fair comparison. People will mostly be biased and tell you that the one that they have is the best!
I have the actifry, and love it. I think it's great, but I haven't ever tried the airfryer, and I think the breville halo is also a good competitor?
Try having a look online - there may be some good consumer advice where people have done fair comparisons/tests and this may give you a better idea xx