Personally, I like to use frozen for "Rockefeller" because 1) the mix is better after sitting overnight, all the bacon, Pernod and juices mingling and into awesomeness. Fresh gets slimy and IMO nasty sitting that long. 2) it takes so much more fresh. 3) the best thing about fresh is, the texture and color, neither matter for Rockefeller. It makes more sense for a restaurant, mass production, but Ive found I still like it better for home use. That is clearly just my opinion and fresh does not suck for this use. Lol.
Sometimes I'll make a Rockefeller dish with a cheese Bechamel and fresh spinach is mandatory! But that's because the sauce is the "umph" that makes everything work.