I’ve gotten chicks from Cackle, Meyer, and Ideal. In all cases the chicks arrived healthy and active. If you read through the reviews section
https://www.backyardchickens.com/threads/breeder-and-hatchery-index.285981/ you will see that some people have problems with all hatcheries, some people are extremely pleased with all hatcheries. Any hatchery that hatches 80,000 to 100,000 chicks a week in season is bound to occasionally have a mix-up but most do a really good job. They will not stay in business if they constantly mess up. So my first suggestion is to go with an established hatchery, one that has been in business a long time.
If you read those reviews carefully you will see that the majority of the problems come after the chicks leave the hatchery and are no longer in the control of the hatchery. A lot of that is due to the post office or airline that is handling the shipment. Sometimes severe weather causes a problem, sometimes an employee messes up. You will notice the complaints go up a lot if chicks are shipped over a holiday weekend. You can’t control the weather and you have to order them so far in advance that you have little control over that, a blizzard, tornado, heat wave, or flood can hit unexpectedly, but you can help your odds by ordering them in the better weather and avoiding holiday weekends. This is why I suggested ordering from a hatchery fairly close to you, to cut down on shipping times and complexities.
You will notice that some of the complaints are more due to the people receiving the chicks not managing that well. They may wait until the end of the day to go to the post office to pick them up instead of going when called in the morning. Or not having the brooder set up and ready for them. I remember one where the kids fed them poisoned food, they blamed the hatchery until they found out about that. At least they were honest enough to admit it. The hatcheries are not always blameless and each is a different business with different managers and employees, but across the board they do a pretty good job.
There are some chicks that can be sexed at hatch by down color. These are not purebreds but are some type of hybrid cross. They often go by the names Comet or Star and often come in red, black, or golden. If you get one of these your odds of getting the sex you ask for greatly improve. But most breeds are vent sexed. That’s where specially trained people look inside the chick’s vent to determine sex. Mike Rowe did an episode on that if you want to watch how it is done.
The people doing the vent sexing are not 100% correct all the time, that’s why the hatcheries give a 90% guarantee on sending you the correct sex. The way I understand it, it is pretty easy to say this one is definitely a male but a little trickier to be absolutely sure one is female so you are more likely to get an unwanted male than you are an unwanted female. The people doing this are going through tens of thousands of chicks in a day so they are in a bit of a hurry. I have not ordered a large number of vent sexed females but I have some. I have had a male but the rate was well below the 90% guarantee. I don’t see my sample large enough to be all that representative. There is some luck involved. Most hatcheries don’t even try to sex bantams, they are too small to see well, especially if they are in a hurry.
Now the sturdy chick issue. Different hatcheries have different people selecting which birds go into the breeding flock so you can get some differences in appearance or other traits between hatcheries. But there are generally productive healthy birds. I am not aware of any hatchery that breeds for longevity of lay so that trait is not bred into them. From my limited sample your odds of getting sturdy chicks is pretty much the same whichever established hatchery you use.
I’ll mention that there are two different types of sex links. One type is made from crossing two dual purpose breeds. These behave pretty much as other dual purpose breeds. But some are made from the egg laying commercial hybrids. These are specially bred to lay a lot of large eggs and be very efficient in converting what they eat into eggs. These are so specialized that they are more prone to medical problems. A lot of people get them and are extremely pleased with them but you might notice a fair amount of prolapse, internal laying, and eggbound complaints come from these. They are great for egg production but in general do not last as long as regular dual purpose breeds.
A feed store near you will probably be having chick days pretty soon. These are hatchery chicks that have already been shipped so you can eliminate that risk. But the issue is that not all feed store employees know what they are doing all that well. You can find some bins that say they have sexed pullets, and usually they are. Most don’t allow customers to pick up the chicks where they can be put back in the wrong bin, but some customers respect those rules more than others. And employees are human, they can make mistakes. By getting feed store chicks you pretty much eliminate travel stress issues but add another layer where there is an opportunity for a mistake to occur. And they often do not have the breeds you want. There are tradeoffs in all or this.
My general suggestion to get healthy chicks is to find a hatchery near you that has the breeds you want to cut down in the risk of shipping problems and be ready to receive them. To me reducing the risk from shipping is much more important than worrying about which hatchery has “better” chicks.