I own and have used the Android version of Gaia. Several years ago I had some sort of problem with Gaia, don't recall what, and switched to BCN. My vague memory suggests that the problem with Gaia might have been specific to my then phone, but dunno for sure.

I've been impressed with both companies, and particularly customer support. Both require some learning curve, neither were, for me at least, super intuitive to learn to use. But with some work at home, a person could master either one well enough to do all sorts of things.

I've not used Gaia for some years, however, so really shouldn't comment much, cannot make a fair comparison. My sense is that both are very good.