Why can't you do both? Derren Brown, David Berglas, David Blaine (and a few more magicians whose initials aren't DB) have done it successfully. It all depends on how you present yourself, and each effect. This is a realisation I only came to recently, and, in fact, I used to argue that a clearly-defined persona would be limited to only a small array of possible effects.
For example, you could even throw in an Ambitious Card routine in the middle of a full-on mentalism set. You could perhaps talk about how you're going to let the audience in on some of your secrets, and how you rely on the mind creating its own patterns based on suggestion. The easiest way to explain this, you tell them, would be by showing them how it could be used in a card trick. You get them to invest something of themselves (maybe call it an "anchor") by signing the card, and get them to take a "mental photograph" of the card on top of the deck. So now, every time you trigger the anchor, they will instantly see the top card of the deck as being the signed selection. At the end of the routine, you could have a kicker where you switch the signed card for an unsigned duplicate, and show them that the pen they apparently used to sign the card doesn't, in fact, work, and it was all a hallucination....