It matters to an extent.
As
@MikeTheBear stated, some bells are just "off," in the shape of the handle, proportions and balance, where they rest on the forearm, etc.
Some other semi-random observations and personal preferences:
--Beware of very smooth thick paint. The smoothness makes the handles hard to hold onto and the thick finish tends to chip and leave big divots that look terrible and are very uncomfortable if they occur on the handle.
--Beware of seams and bumps in the casting, which are very uncomfortable and can tear up your hands.
--A lot of KB brands, especially in powder coated cast iron bells, including Rogue and Kettlebell Kings, seem to be made from the same generic design, although there will be variations in the molded branding and the texture of the powder coat. I have no experience with current Perform Better, but they look similar in pictures. I have some horrible older Perform Better bells that are a different design, with thick paint over lots of filler, vinyl coatings and a rubber bumper on the bottom.
--I believe the original DragonDoor KBs (16, 24, and 32kg; other sizes came later) were molded after Pavel's own KBs. The current generic KB design works fine, but is NOT the same. I have seen a post here from someone who bought a Kettlebells USA Metrixx Classic E-coat bell to match a DD KB and reported they were virtually identical. So if you are looking to match a DragonDoor, or like the design, but don't want to buy DragonDoor, that's were I'd look.
--Powder coat can have a very nice handle texture, but is not nearly as durable as the E-coat used by DragonDoor and Kettlebells USA. My powder coated bells from Rogue all have significant chips and peeling, whereas my E-coat bells, some of which are MUCH older, have small dings and wear spots, but no chipping or peeling. In use, the chipping and peeling is not really a problem since it hasn't happened on the gripping part of the handles and I don't feel it at all, plus the powder coat is thin (a good thing in this case) so it doesn't leave a very uneven surface or big divots when it chips.
--I have become a big fan of the Kettlebells USA Paradigm Pro Elite Precision competition style bells. I now have a few pairs of these, and I ALWAYS reach for them instead of my cast iron (mostly DragonDoor and a few Rogue) bells of the same sizes.
The 35mm handles (they also come in 33mm) are "right sized" to me, a little smaller than standard cast iron, and very comfortable without feeling thin in my average sized hands. The bells rest on a comfortable spot on my forearm, and the texture of the bare metal handles is smooth, but with a bit of grain to it that works well with or without chalk, and isn't slick like some very polished competition bell handles.
Some surprising things about them are that they have more room and are more comfortable for two hand swings than my cast iron bells, and that they are easier to keep from clinking together when using doubles.
--Kettlebells USA also has a cast iron Metrixx Elite line, which is supposed to be designed with more space for two hand swings and proportional handle windows so that all sizes rest in the same place on the forearm. I have no personal experience with these.
--I don't think you can go too far wrong with the generic powder coated bells from a reputable/popular source, and they are probably the best value for a lot of people (a servicable bell at the lowest price). However, it is definitely worth it to ME to spend more for the bells I like the best.