I suppose the DIR philosophy is more GUE right? I don't know much about those guys or really know of any instructors. I didn't want to ask in their forum as it would definitely be biased. I chose an instructor on my past certifications, so I'll do the same for the rest. Thanks.
If your profile is accurate, my first recommendation is to get more OW experience before considering cave ... it's a whole different mindset, and being completely comfortable with OW skills is pretty essential to making a reasonable transition.
As for choosing an instructor ... it's really important, more so in cave than in OW, to choose an instructor whose teaching style matches your learning style. Even a great instructor might not be the right one for you. Classes are something of an artificial environment, and if you're constantly playing a game of trying to guess what your instructor wants from you, you lose the essence of what he's trying to teach you. Physical skills are important, but in a cave the mental skills become increasingly important ... despite extensive experience, I was held back on my first attempt at Full Cave not due to my diving skills, but because my mental decisions that weren't quite up to my instructor's standards. Rightfully so ... it's a different environment, and requires a different way of thinking ... and making bad decisions is what usually gets cave divers killed.
Research the different agency programs, sure ... but the differences between instructors will be somewhat greater than the differences between agencies. So interview a few different instructors. Ask them what their prerequisites and expectations are. Ask about the skills taught, how they're taught, the format of the class, the equipment requirements, the number of dives conducted, and contingencies for not passing on the first try ... the good ones will be quite specific in their responses. If someone's vague or evasive, keep looking.
I could recommend my instructor ... I think he did a great job. But he might not be the right instructor for you. Same with everybody else in here ... they might have felt they had a great class ... but you aren't them, and how you interact with your instructor may not be the same as them. Only you can make that determination.
Whomever you choose, go into it prepared for a class that will be physically exhausting, mentally stressful, and demanding of more than your best efforts. Good instructors stress and press you. They're not doing it to be a hard-ass, they want to find out how much stress you can manage without breaking emotionally ... because responding calmly in an emergency will be the difference between living and dying if you should have one ... much more so in a cave than in OW.
I guess what I'm trying to impress is that I look at your profile and think "hmmmm ... should someone with 25-49 dives be thinking about cave diving?" Probably not yet. It's a great goal, and one I wholeheartedly encourage ... just take it slow. Learn where your limits are in OW first ... then think about finding the right instructor to help you expand them to the more demanding environs of a cave ...
... Bob (Grateful Diver)