Going for EXP is far less risky than sticking with UA. Yes, there's the possibility that AA will dilute EXP somewhat. But there's the certainty that UA has diluted 1K tremendously and that it will make 1K even less valuable over the years. Plus EXP is simply a better status to have than 1K, in terms of upgrade potential, far better phone agents, being the top tier within AA (as opposed to 1K being second fiddle to GS at UK), etc.