Here's the deal: If you want to progress efficiently, take cave first. If you can plan a multilevel dive with mucho deco obligation, then you know and understand how to conduct a safe dive. Anyone can do a square profile and progress up in a staggered way. Again, I would suggest learning to dive caves first. Although you may not believe it now, if you can plan a multi-level cave dive, you can plan almost any dive that you will do. I don't know many cave divers who don't understand deco theory fairly well, so I think the two go hand in hand.
For what it's worth, I was doing deep mixed gas in cold water with strong currents and 20+ foot tidal changes before I did any cave diving. I moved to Florida to gain proficiency in a cave. Now, the dives that I used to worry about are a piece of cake. Caves necessitate an understanding of planning that goes beyond following a computer printout.
I can't say enough about the experience of the class alone, much less the learning experience of being around people who do multilevel decompression dives several times per week. I'm doing an internship to teach cave and mixed gas now. I will urge all of my students to do cave first. If not with me, with one of the many qualified instructors who are available. There is no class that disciplines divers like cave.
Cheers,
Jamie