IMHO there are FOUR kinds
1) Cheap chinese or other junk that come with throw away socket sets.
2) Wobble..HATE them for any reason other then when wobble is needed.
3) Ones with knurling..on top is nicest, but not matter really
4) Everything else. Craftsman, Duralast, Cornwell, Husky, Proto, Harbor Freight and so on.
Really, they are all the same and every single one from any half way decent quality is a good as the next. Really, any 3" extension good enough to have any name brand on it is fine. Just pick if you want knurled or unknurled....any brand. Does not matter. The fastener is going to break LONG before the the extension unless you are doing something like a 1" socket on a grade 8 bolt with a pipe on a 3/8 breaker bar.