Can’t speak for the non pet side, but for pets, I would recommend going for Conjurer instead based on personal experience unless the decision excludes it.
While all 3 combinations are strong in their own right and every major patch seems to bring about a shift in balance, Pet Conjurer remains the easier to both gear up and get started with if you are new. The Pets are easy to build around (except hellhound, but that is a different issue), have auras to support you and your minions, the skills are easy to play with and there are many choices in regards to what damage type you want to focus on.
Now Cabalist vs Ritualist… that is a bit trickier.
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Ritualists:
For a long time Ritualists were seen as incredibly weak. But that has all changed and they are pretty strong atm. One thing that I have found is that Ritualists, when it comes to pets, tend to be… quirky. If pet Conjurers are straightforward to build and play, pet Ritualists, atleast imo are anything but.
First things first, your Pets will be starved for Health, Resistances and a good chunk of Total Speed (you get an obscene amount of pet crit as compensation though, from primal bond). Skills, if you are like me (lazy and likes to play while eating…) you will find them harder to use… like much harder. If you are not going for a Vitality Pet build, I don’t see much point in going for a Pet Ritualist. On the other hand, if you are going for a Vitality Pet build, Ritualist > the rest imo.
I won’t comment on Skeletons since I find them to be absolutely useless atm and I might be biased on my opinion on it because of that. But you can play around with Immortal Reap Spirits (high Crit and Vitality focused) with Diviner’s Set or Ghol Set based Exploding Blightfiends (Acid/Poison based and imo better on Cabalist). For non exploding Versions of the aforementioned blightfiends, I would rate Cabalist to be a better option as you want to keep those alive. Regardless, your experience would be more similar to playing a Caster with auto targeting spells than a proper pet build with Ritualists. Expect to do alot of button mashing too and Devouring Swarm is just painful to use as a tool for reducing enemy resistance… but it is kind of needed on a vitality pet build, so not much option there.
One thing I should say is that for the player atleast survivability is pretty high here compared to a Pet Cabalist. You will have a high amount of Health, DA, Healing etc for the most part and the disposable swarm-y nature of your minions help a bit too.
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Cabalists:
For a long time they reigned as the king of DPS when it comes to Pets. But a series of nerfs to what made them that strong and buffs to competition has leveled the playing field. You will find them easier to build and play with compared to Ritualists even if not as much as Conjurers. They are sort of in the middle when it comes to having access to different damage types also.
You trade the beast of an Exclusive skill (pun intended) and the Mog’s Pact line from Shaman for the insane Pet support offered by Occultist. You won’t miss the Wendigo Totem too much. Blood of Dreeg and Curse of Frailty will quickly end up being your best friends too. Now, I mentioned Ritualist Pets ending up with less health, resistances etc… At first sight, you will see (or assume) that you won’t be having that problem here. While that is true when compared to a Ritualist, it is also not that true since you are pretty much trading some things for others, like the bleeding, pierce and aether res from shaman for elemental and acid res, crit for total speed etc… Health is the only thing that really applies, but it is not really something that makes too much of a difference in practice when you consider the pets you have to work with.
You will however find yourself having more freedom with the endgame build and item choices here. Personal favourites are Familiar + Reap Spirit (Elemental with the full Diviner’s and Bysmiel’s sets) and Exploding/non-exploding Blightfiends (acid/poison with Ghol set). Chaos and Vitality are also both possible though I can’t speak for their strength in the current patch. You will find the skills easier to play with and you can choose to go for a more Caster like experience or a pure Pet build like playstyle (as in active or passive, not a hybrid Pet/Caster).
However one major thing I have noticed is that the player’s Survivability is actually not that good here. Ghol Cabalists can be cited as an exception due to the insane nature of Transmuted or in other words, Unstable Anomaly based Exploding Blightfiends, but that also applies to Ritualist. While you can compensate the lack of Totem with Familiar and Blood of Dreeg healing, you still need to avoid getting caught out and unlike the Ritualists that might still pull through, here you are most likely going to die if that happens.
Ok, so I have written a small wall of text up above and you might be wondering what my answer on Cabalist vs Ritualist is. What I can tell you is that I don’t really have one. Both play differently and at the same time are also similar. If you want to go for the one that is better, in my eyes that means the one that lets you afford to make alot of mistakes and still steamroll content rather than the fastest clear time vs a particular boss or game mode or whatever… and for that reason, I will still recommend Conjurer. Pet conjurers can do what the other pet classes can, with their eyes closed and face slamming on the keyboard. The only place where they will fall short is when faced with a situation where your pets die faster than you can resummon them and kiting while waiting for CD is not an option. In other words, for high SR, Pet Ritualists and Pet Cabalists might outperform due to the nature of Blightfiends and how strong Ghol’s Malice set is. But if your goal is below SR 100, then I would say Conjurer all the way. Dark One set based Pet Conjurers can also offer a different kind of playstyle based on a more support oriented role for multiplayer should you choose to take that route or simply do not have any other set or items to use in its stead
Oh and as a parting note, let me also say that Pet Conjurers can also provide with a bit of active playstyle if you want to build it that way. It is just that it tends to be unnecessary for the most part unless you want to go with a lot of pets (basically a zoo) or want to play with a Bleed Pet build. Anyways, I will stop here before this becomes even longer. Feel free to ask if you have any questions or further queries or simply wish to feed me ice cream :3