Hi scgsgsparky,
I think the short answer to your question is "of course it does!" That said, I have no idea what you plan on doing with your ESXi box, but you should never short yourself on disk I/O.
Whan you get down to it there's only a couple hunderd dollars difference between the 2 controllers which might be 5-10% of the total cost of the system you are planning on building, but the addition of the battery backed cache will make a huge difference in the systems performance. Don't short yourself & the project from the start.
-Will