I have a 20 gal SS Brewtech kettle and I love it. The temperature probe is a little high on the kettle if you only plan on doing 5 gallon batches, but everything about it is sweet. The gallon markings on the side are clear and accurate and the trub guard at the bottom is a pretty nice option to get as much clear beer into the fermenter as possible.
But like some of the other posters have said, I wouldn't limit yourself to just SS or Anvil. There are some other really good stainless steel kettles that might be just as good, if not better, but could be a little cheaper.
I don't think you'll go wrong with whichever kettle you decide on.