To my own suprise I am totally a franchise player. In other games (Wildlife Park series, ZT2,PC, Cities: Skylines, The Sims series...) I would usually only/mainly play sandbox or use cheats. So when they announced Franchise Mode, I was sure I wouldnt use it anyways and was disappointed that we couldnt use sandbox during the beta.
However, during beta already I got to like it^^ Unlike some other games I am even able to make some money
I also like taking part in the challenges and that the animals I trade are just not simply deleted from the game and help others to breed new/better animals.
Also I am totally into breeding albino animals and that is pretty hard in the other modes. Its also great you can send the animals to your other zoos.
It is however true that franchise mode is less stable and crashes more often, at least in my experience. Its also a bother that you have to research everything again and again for each zoo.
Oh, and not to forget, at least for me, flippers ruin the fun a bit aswell.
But all in all it is very worth it for me.
About the complaints, well its true there are complaints that are user-errors, but there are also genuine ones. I mean take for example the loading bug, many sandbox player tried to blame it on the hardware of us who had this problem.
Or my zoo were I had the protester bug, some players were like I should just care better for my animals and then the protester would leave or I should just delete the zoo.
Most of the complaints about feeding issues are problay user-errors, but not all. I also noticed that, sadly, huge habitats, especially with mixed species, are getting a straving problem sooner or later. Which in my opinion is design flaw how the keepers/feeding works. Also sometimes animals suddenly refuse to drink, even when lots of water is available. Loading the game new often helps to slove it, but its still a bother. This problem was gone for some time for me, but yesterday it happened again. Though this might not be a franchise only problem, though.
And I also dont think there are that many very negative complaints, anyways.
However, Franchise is pretty much the main mode of PZ. Thats just a fact, considering how Frontier advertised it and cares about it. So it should also work properly.
I think Frontier already made great improvements to make it run smoother.
Afterall I still enjoy Franchise very much and I prefer it over all modes

But I am also more of a breeder and not so much a builder, so thats also a reason, I guess^^