I totally agree with masterkiller in regards to forms being the best way to develop your endurance. By doing forms slow, and in a deep horse only allows you enough endurance to complete the form. While circuit training will enhance your overall endurance.
In fact, my students practice their sets both super slow and super quick. And, their just winded at the end. But when i include circuit training along with forms practice, my students have actually vomited immediately after a semi hardcore type of circuit training workout.
To be a more complete martial artist, forms are only one aspect of being one. It's one thing being able to perform a set or form crisply, strongly, and explosively. But, what good will that do you if you have no clue in how to use what you just performed?
However, I still love my forms. When you're alone, practicing a form is a very personal experience. No joke. You can get lost in a form, and actually become the form. Yet, as i always say, forms are nothing more than the blueprints of the system. a good carpenter or architect would look at the blue print, get to know it, and then when it's absorbed, are able to modify it based off his or her own knowledge of what they've studied and trained for. it;s at the point you can take from your forms, and learn various ways to use what's in them.
Hung Sing Boyz, we gottit on lock down
when he's around quick to ground and pound a clown
Bruh we thought you knew better
when it comes to head huntin, ain't no one can do it better