Voice over is more consistent imho. Talkback can differ depending on the type of phone. iOS is also highly regulated and standardized where android and other such devices can be more open source which leads to issues that iOS just doesn’t have. That said. Technology is fickle. And sometimes wanting to throw it through a window when it doesn’t work is highly justified.

A big part of it for me is the way both products are being kept up to date. VoiceOver is VoiceOver no matter where you go. Talkback, or technically speaking the Android Accessibility Suite now, is phone-dependent, Android version-dependent, which means you might be stuck with a problem you're having for an extremely long time.
This will probably get me grumbled at but I also feel VoiceOver is being updated at a more consistent clip than Talkback. VoiceOver is an Apple product, and therefore user feedback pretty much ends up in a black hole when it's submitted and nobody knows what will get fixed when. Generally though, if bugs are introduced in Voiceover, the majority of them will get fixed reasonably quickly, whereas I feel Talkback, in part due to what I just said regarding fragmentation, just doesn't have that same rapid clip. Users have been asking for things for literally years and a week or two back a blog post gushing about how user feedback was acted on just leaves me feeling decidedly meh, because yes they did up to a point, but that feedback has also been there for years.

It's hard to precisely pin down but Apple's accessibility commitment feels more steady whereas with Google I just don't have the confidence they can and will pull through when the going gets tough. See also randomly killing accessibility features on Youtube, completely breaking accessibility on Google Groups for a while ...the track record just isn't very good that this is in their DNA and it gives me the feeling that Talkback is this afterthought friday-afternoon project that could be great, but just isn't.

I use VoiceOver every day for my personal use, and use it along with TalkBack and Samsung Voice Assistant for testing for work. There really is a difference between the screen readers, and it's very apparent that TalkBack and Voice Assistant was engineered while VoiceOver feels Designed. VO is very intuitive, is fast and easy to use, plus it integrates well with other Apple devices. TalkBack is a crapshoot due to the differences in all the Android devices out there and flavors of Android itself.

VoiceOver has a much larger breadth of gestures that can be controlled and customized along with the ability to change functionality and verbosity per app with Activities. TalkBack doesn't really have this and has much much less in terms of gestures since they don't allow multi-touch or multi-finger gesture editing, at least as far as I can tell with TalkBack 9.2.

This is a personal preference, but I've always found the VoiceOver voice synthesis to be much easier and more pleasant to listen to over the TalkBack/Google voices, especially at high speaking rates. The VO voices are much more natural and accurate. The Samsung Voice Assistant voices are just hot garbage all around.
As already mentioned in another comment, VoiceOver works much better with websites and is much faster for app interaction. TalkBack, even on native Google hardware like Pixel phones, seems laggy and markedly slower through web views and apps. One little bit of anecdotal interaction comes from evaluating how VoiceOver and TalkBack manage the address bar in Safari and Chrome respectively. In iOS, I'm able to double-tap in the address bar and edit and navigate the full URL. Using the latest version of TalkBack in Android 11, I am fully unable to edit and manipulate URLs in the Chrome address bar. If I happen to have the TalkBack braille keyboard toggled, double-tapping the address field brings up the keyboard but removes all text-editing abilities through the text field, effectively stopping me from making small edits to an address and forcing me to retype the entire address. If I switch back to the google QWERTY keyboard and try moving the text cursor with the volume buttons, etc., I've already lost the whole address and have to retype it anyways.

Just little interaction differences like this are examples of the huge divide between the screen readers and operating systems.

Websites in TalkBack are super slow

These days? I’d say no. Put it this way, both companies have usable phones.

I prefer IPhones but don’t like the company.

You may ask, why not switch? Now we come to the issue with android. Most of the phones don’t come with talkback installed so a blind person must either get a sighted person to click on accessibility/talkback and turn it on, or to download it.

Many Android users will say there is no difference. many IOS users say there is a huge difference. I believe there is a massive difference.

Voice over is a bit more well defined and has certain limits so it makes it easier.

I've used both and they are comperable. VoiceOver is probably easier to pick up from a beginner standpoint, but TalkBack is just as useful.

I think most of the complaints either way can be put down to just people's familiarity with either system. That sort of muscle memory takes a lot of time to build up no matter what you're using. We all have our favourite cane tips too.

Personally I've always been an android person but only because apple is so fricken expensive and makes it annoying to load files on and off your phone.

I used talkback for about half a decade before switching to voiceover. The screen readers themselves are competent, but voiceover is more rich in features. They both have aspects that I like and dislike, but voiceover feels like a little more thought was put into it. The problem with talkback comes from the variability amongst different hardware vendors. A Samsung will have slightly different accessibility compared to a pixel or a OnePlus . That variability can be very frustrating. That’s not to say voiceover is perfect. In my time using it, I’ve had stability issues and bugs that simply don’t exist on talkback. Text to speech and speech to text are also a bit worse on the iPhone side. Still, having mostly competent braille support and an entire community that I can go to for tech support are more valuable to me than what android brings to the table.

In my personal experience, yes. Whilst Voiceover is steramlined, intuitive and has easy to learn gestures, Talkback has a full-on learning curve making it hard for me to switch seamlessly between the two or remember how to do things on the latter that should, theoretically, be extremely straightforward. Granted I've been an IOS user for a long time, but that shouldn't make a difference really if Talkback wants to be as intuitive as it is sometimes seen as.