I get a wide variety of kits due to shopping at garage sales, quild sales, ebay, etc. It helps that I dont have an issue with adding fabric or changing fabric and dont like matchy matchy quilts. I want a large variety of fabric in my quilts.
The absolute best are Homestead Hearth kits. Every tiny piece of fabric or small group are labeled. It is so time consuming to do this but their kits are the best. I would never have a problem buying one of theirs. Our southside shop tries out each pattern before making up a kit and have found a variety of problems and fixed them before putting their kits together so I trust them.
I have a couple of favorite sellers on Ebay that make up kits and they are great too.
Worst kits were from the big time manufacturers who try to skimp and save. They are more likely to be "short" and it is mostly because of the savings they are trying to get out of labor and materials. They also tend to be more matchy matchy from one line of fabric and harder to "add" to when short.