I think the 5x5 classifier is a nice skill drill to shoot once in a while.

I prefer the 90 or 72 round versions of the IDPA classifier as a more comprehensive measure of skills.

I really like to shoot USPSA special classifier matches. Regular club matches don't interest me that much any more, but I really enjoy shooting classifiers. Shooting classifiers is like dating; l love them but they don't usually love me back.