I purchased the deluxe locking caps. They are beautiful and easy to open/close. I've read reports where folks had trouble opening their standard caps with their fingers or had to use a tool. Absolutely no problem with the deluxe caps.
I've also read reports, like JonJay above, that the retro-fit locking caps with their flange that bonds into the existing flange hole, leave an opening that is too narrow for certain fuel pump nozzles. Like he said, probably not a big issue if you decide to go that route.
Yes, the deluxe caps are kind of expensive. But they're great and I'm glad I have them.