I had one of the 6-chamber round ones, very like this, which I hated:
https://www.ebay.co.uk/itm/115555914333?hash=item1ae7ab525d
- it takes large C batteries, 4 of them, and is very inefficient in energy, as it has to turn round the whole thing. So you would spend a lot on batteries, and I wouldn't have trusted it not to run out, if I was leaving it for a couple of days, for example. (Not an option now anyway, since the cat needs her insulin).
- the slidey opening thingy baffled me. Altogether, an over complex design and I didn't trust it.
I just got hold of a 2-chamber Petsafe and I love it.
https://store.petsafe.net/automatic-2-meal-pet-feeder
It takes ONE AA battery, and only has to turn the little dial till the lid flips open, so is much more energy efficient - although, there seems to be no way to turn it off, so in order to save batteries, I take the battery out when it's not in use. (I've written to Petsafe to ask if there is any way round this).
I've seen some bad reviews, quite a few people clearly received duds, though beware that many of the Amazon reviews are for different models, like the rotating ones with more chambers. Also, I saw some videos of cats and dogs who had figured out how to attack the dial and get the lids to open! My cat is however no kind of genius, and I would be completely amazed if she figured that out.
Mine works fine and I'm happy with it. In fact I've ordered another one, on the assumption that one day we will actually go out for a WHOLE DAY

- and I currently feed Footfoot about every 3 hours during the day. I use the Petsafe feeder to give her a meal at 5am.