Let's jump right in with a list of A55 behaviors that are undesirable. These can be either bugs (undesirable things that Sony did not actually intend the camera to do); limitations (undesirable things that Sony probably knew about but could not overcome with present technology); or oversights (undesirable things that Sony certainly knew about and could have fixed, but failed to address). There could also be a much longer list of missing or poorly implemented features that Sony should have and easily could have corrected in hardware or firmware; but all cameras suffer from this and probably always will.
Bug 1: The very first thing you should do when you get your A55 is turn off Auto Review! Auto Review is unnecessary with SLTs because you're always seeing a simulated, adjusted view of your final shot. Leaving it turned on adds a very annoying delay to even the most casual shooting. I don't know why this is the case, and I don't know why Sony decided to make it default to on. Turn it off, and press the Play button when you want to review something.
Bug 2: The second thing you should do is obtain and apply the firmware version 2.00 update if that has not already been done. With the original firmware, HSS (High Speed Sync) autoflash did not work correctly in wireless mode. This particular problem was corrected in the update, and some other nice features were added as well.
Bug 3: When the camera is set to Auto or Auto+ mode, and flash is active, the camera chooses a shutter speed and aperture that are appropriate for the ambient lighting. Because of this, when the scene is dark or dimly lit, the shutter speed can become absurdly slow in order to obtain correct ambient exposure. Then the flash fires as well. The result is a shot that can be both blurred and overexposed. Very bad, considering that these modes are intended for users who generally know little about the mechanics of exposure and flash use. This will not happen in 'P' or 'A' modes, where the camera does not allow the shutter speed to drop below 1/60 second when flash is active.
Limitation 1: The live view image shown in the EVF and on the LCD is always a fraction of a second behind reality. Depending on lighting conditions, the delay might be either imperceptible or as long as 1/10 second. This means that the user may need to anticipate action shots that require precise timing. It's not Sony's fault, though. At present, this type of delay exists in all electronic viewing systems and is unavoidable.
Limitation 2: There is an additional delay whenever a recognized dedicated flash is used (either the pop-up flash or a Minolta/Sony external flash). This delay occurs between the moment the shutter button is depressed and the moment the exposure begins. Most people have estimated the delay at about 1/6 second. It's not clear why the delay exists, and perhaps Sony could do something to eliminate it. There is no such delay when using non-recognized flash units fired with cables or radio triggers.
Oversight 1: When in 'M' mode, the camera attempts to show you the exact exposure you will obtain based on your settings and the ambient lighting - unless you are using a recognized dedicated flash, in which case the camera will automatically 'gain up' the display so you can see the scene. This is a good arrangement in many situations. But suppose you're shooting in a dark or dim environment (like a studio) while using external non-recognized flash units. The camera doesn't know about those, so it will continue to show you a very dark and sometimes unusable image. Sony should have included an option allowing you to force the display to gain up in such situations. The company is definitely aware of this oversight because it also exists in all previous Alphas that offer live view, but at least those cameras offer the option of using the optical viewfinder instead. The important difference with the A55 (and A33) is that these new cameras have no optical viewfinder! So, until this is corrected, here are some workarounds that will force the display to gain up...
Workaround 1: Set the shutter speed to 'Bulb' and shoot with the fastest start/stop time you can manage.
Workaround 2: Move the mode dial one notch to 10fps mode for focusing and framing, then back to 'M' for the shot.
Workaround 3: Raise the pop-up flash before you attach your flash adapter. This is possible because of the new flash hinge design, as shown below. Then cover the pop-up flash if you don't want its light to contribute to the scene.