I personally would rather buy a named cultivar as suppose a general or unknown one.
It's good to know if they are early, mid or late so you can have a long harvesting season and as you mentioned above to know what you have for cross pollination purpose.
And last but not least if you ,like me and many others, get the blueberry virus you will keep buying more plants to add to your collection so knowing which one you already have would be an advantage.

I have spoken to the person that ordered the plants and it turns out that some are Brightwell and some are O'Neal. I understand that O'Neal are semi-self fertile but will benefit from cross-pollination with Misty.

In my experience, as long as two varieties (including rabbit-eye and southern high bush) are flowering at the same time and there are pollinator bees are available to pollinate them, they will set fruit. I have Climax (RE) and other southern high bush varieties that were flowering at the same time and I was wondering if my Climax would set fruit without another RE variety flowering in the vicinity at the same time. Despite reading most articles stating you have to have another RE variety as a pollinizer for RE to set fruit, I am glad to know even SHB is good enough for RE to set fruit.

inkfin, thanks for the feedback. I will just google a bit to check if the RE and SHB cultivars are flowering at the same time. What soil mix are you using? Apparently the RE gets to big to be grown in a pot but I am tempted to try it anyway. My soil does not drain.

I use 5 parts composted pine bark mulch, 1 part peat moss, and 1 part perlite with a handful of sulfur to grow my BBs. No soil. RE can be grown in large (20 gallons and above) nursery pots. Blueberry will die if the soil does not drain. You can search how to grow blueberry on gardenweb forum and there are lots of BB experts have contributed their great experiences.

These two are great links here (and there are many more):

http://forums.gardenweb.com/discussions/1969166/blueberry-lovers

http://forums.gardenweb.com/discussions/1896245/growing-blueberries-in-central-florida?n=26

Good luck!