Kinda depends on what type of riding you're doing.

I've only been riding for a couple months but took the plunge after several cyclist friends urged me to get them. They all commute to work and participate in centurys/triathlons, which is also my goal.

With that said I started with platforms, so whatever my .02 is actually worth.

If you're casually riding and commuting platforms are more than fine. It will also save you some $$$$

If you're looking to maximize performance I would recommend them. You're going to have to develop technique though, and that takes time. I'm still learning myself. My speed picks up 1-2 mph when I consciously engage my hamstrings and it also eases up the load on my quads. I can shift the burn throughout my leg. It helps a lot when fighting head winds or going uphill. When going uphill and keeping my cadence up I'm 2-3mph faster.

A buddy loaned me a set of rollers that I use during bad weather days and practice technique.

I've noticed a notable improvement in performance.