I realized I am getting into more challenging worlds and I should get a better pet. But I can't really decide on which one to choose (all so amazing!), so which one would have the best stats? Thanks
The only way you can get a truly amazing pet is to hatch it with other pets and train until you get the talents you like. All pets have useless talents that you can't use, some more than others. If you don't want to get into the hatching process, use a pet of your school. That way you won't end up with fireblade, fire shot, fire dealer ... Try training the level 48 or 58 pet up.
Stats are the attribute numbers for individual pets. Higher, up to 250, gives more value to talents that boost your stats like resist or damage. They don't matter to may-casts.
As far as what kind of pet and what talents, that depends on what you need. I usually want a pet that gives a blade or trap I can use, or the Enchanted Armament which gives sharpen blade. Popular talents are resist (especially Spell Proof) damage boosts like Pain Giver and the dealer for your school, and healing may-casts. You might also want a Shot or Sniper talent if you have trouble with fizzle. There are many other things that could help too, but to start out those general talents are good.
You can start with Starfish (for gold) or a Sea Dragon (for crowns) then hatch with pets that have exactly what you want. Usually you'll have to hatch a few times (or more) to get all the stuff you want, but each generation should get better. Don't be upset if some don't turn out well. Pets are really a long gradual project.
I think that the frost caller is a good healing pet and that also the best way to get an OP healing pet is by constantly hatching with other good healing pets
It's different for everyone. Start off by thinking about what talents you want and what kind of card the pet gives. Also if you are planning to use the same style/pet on different wizards? By hatching it a few times copies can be made pretty easy. You may still get fails but at least easier then changing up completely. If doing that go for a balance blade type pet or some other general use pet. If just using it on a specific wizard you might look at a pet with the school blade or other school cards. Also do you want extra damage, resistance, healing, etc? A little bit of planning can save a bunch of time later. As to stats most of the time the higher the better. And you can work to raise stats for any pet.
I realized I am getting into more challenging worlds and I should get a better pet. But I can't really decide on which one to choose (all so amazing!), so which one would have the best stats? Thanks
Since no first generation pet is ever perfect, most experienced players hatch many times to cultivate the talents of their perfect pet. The Sea Dragon has very good pedigree, talent slots, and max ability numbers, so it is one of the best first generation pets. I would suggest getting one of these to start your customization process.
If you want the best pet, its about who you are really. if you have high health you probaly looking for a damage pet. If storm probally resist and heal. i would recommend resist and healing. damage and resist. damage and healing. resist and heal and damage. power pip and resist. what you want if you're any of school above is probally 1. spell defying 2. spell proof 3.fairy 4.sprite 5. maybe pain giver or your own school giver. hope all that helps :)
you probaly looking for a damage pet. If storm
probally resist and heal. 
i would recommend resist and healing. 
damage and resist. 
damage and healing. 
resist and heal and damage. 
power pip and resist.