I'm looking at creating a simple platformer game on the Android platform, however, I'm trying to think of some method of control. I've seen some games use a virtual control with buttons on the screen, and others that use the accelerometer. Which would be your personal preference if the game was similar to Megaman (the classic series and its sequel series) or Sonic?

Note, this is for devices that don't have physical keyboards/buttons, such as the Galaxy S2 or the Nexus. Devices with keyboards or pads would obviously use them, unless the user opted otherwise.

The one I've come to like most is the one used in Giana Sisters (the android version of the Super Mario "homage"). It is basically a virtual keypad, but it origins at the point wher You touch the screen and offsets from there. This is for the left hand side of the screen, the right hand side of the screen is used for jumping (touch anywhere to jump) or fire weapons/use extras, by clicking on their respective icon. When You donät have any weapon or extras, jump will work anywhere on the right hand side of the screen but when You get a weapon or so, an icon appears and is then used to invoke that item.

I have tried the accelerometer approach in a couple of games and also done that my self, and some times it works quite okay, other times not so okay.

What stuntcomposer mentions is (at least IMHO) where the best of virtual controllers have gone in recent times - offset from the point of first touch for stick controls, with a re-origination when the touch is lifted/re-applied.

For the right hand controls, they can either be completely different or often are just a derivative of what is going on with the left stick/left side of screen controls, with perhaps differentiation only on based tap/double tap, boundary of deflection limits and of course - the in game action it's applied to.

I would actually consider tap/double tap for jumping or different types of jump - due at least to these actions being surprisingly intuitive and often more so than movement or deflection (virtual stick deflection).

I'd also consider that some platformers only need left/right for movement, but you could also control the duration or a jump via the up on the left side (up deflection), or also experiment with up deflection on the right side (potentially in combination with tap/double tap derivatives).

In some ways, I'd also say...why ask a question like the one you've asked? You mention you've tried accelerometer stuff in the past. Keep trying different things - through experimentation and iteration the best methods will rise to the surface. Not only will this make the game better, but the experience personally gained from such a process makes you a much better designer and implementer.