Our DD is 4 and we have had an ABA consultant for about a year. I'm not sure this is really "ABA Therapy" as we don't have any therapists - she's been giving us parenting advice really, but using ABA principles.
For us I'm not sure it's been that different to normal parenting as DD is motivated to do this stuff (socialise, try new things, etc.) - she just finds it hard but she wants to. She likes all the normal kid stuff (stickers, praise) so we basically just do it all through reward charts and saying "good job!" when she manages something she finds hard, etc.
The main benefit I've found is breaking things down into tiny steps. So e.g. DD finds socialising hard. She was always interested in other kids in playgrounds etc. but didn't know what to say to them. So we found the ABA consultant very helpful in suggesting ways to break this down (e.g. first ask name. Then work on getting DD to tell her name back. Then ask age, etc.). They've also given us useful ways to practice turn taking, answering questions, gentle ways to work on rigidities that seemed to be upsetting her, etc. They've also suggested some good things to work on thinking about figuring out emotions (e.g. doing a daily diary where we talk about the best thing and the worst thing from the day, talk about how it made her feel, draw pictures of it, etc. and ideas on how to use story books to talk about emotions that the characters are feeling).
The thing it reminded me of most was the physio we did with her when she was small and late to walk - building the muscle groups she needed before she could stand independently and take steps.
That said, I definitely think there are problems with ABA, and maybe even with ABA as we are doing it. The good thing about delivering it yourself is you can at least make your own judgements about what you are comfortable with and what your DD is comfortable with. What is actually helping her and what is just trying to "normalise" her for the sake of it? We have rejected anything "anti-stim" for example.
For me it's an uneasy balance between trying to teach her skills she might find useful in making friends and socialising (which I know she wants to do), but not at the expense of making her feel that she is broken/wrong/inferior. I think the closer we can get our kids to a cast iron self-belief the better for them, as we know the world is continually going to try to knock them back. We need them to have the strength and energy to be able to get back up and be confident as their "true selves".
I think the problem with all these "therapies" is there is actually very little good evidence. Although ABA has some evidence for "efficacy", what the original researchers considered "effective" might not be what you want for your child or what is good for their mental health longer term.
At the same time I struggled a lot with social stuff as a kid and wished that somebody had "taught me the rules", so I'm also disinclined to think we should just let DD "get on with it". I feel like there must be a way to help our kids navigate social stuff, without trying to cram them into a box that isn't comfortable.
Sorry... bit of an essay! But it's a tricky subject I think and there is not a great evidence base to go off, so a lot of it has to be your own judgement.
If you are interested in that kind of distance service the people we use are "Beam ABA": if you have questions feel free to PM me. I don't know anything about the more traditional desk-based/intensive ABA other than what I've read. I follow a lot of autistic people on Twitter and YouTube and the consensus generally seems to be anti - but not exclusively.