Moving up from SLT-A55

Some more info about your pictures in the last year can help us and you. Are they jpegs only or raw processed with DXO or Lightroom. I found the raw processed in DXO better than jpeg only.

What mm are most of your pictures at? If they are at say 45mm then perhaps a Sony 50mm F1.8 prime lens will give better image quality than 50mm on the kit lens. The 35mm F2.0 and 16-80mm Zeiss give me definitely better color and contrast than the kit lens, whether jpeg or raw processed. I never liked the 18-55 kit lens, pictures looked too clinical to me. The 100-300mm APO D lens has given me good pictures, though I don't use it much.

Minolta's small 135mm F2.8 gives 202mm F2.8 on aps-c.

Even DXO says there has to be a good percentage increase to notice.

"A color sensitivity of 22bits is excellent, and differences below 1 bit are barely noticeable."

"A value of 12 EV is excellent, with differences below 0.5 EV usually not noticeable."

"A difference in low-light ISO of 25% represents 1/3 EV and is only slightly noticeable."

http://www.dxomark.com/index.php/About/Sensor-scores/Use-Case-Scores

The consensus on the net is the A77 jpegs lose too much detail and aren't any better than A33/55/57 jpegs, but the A77 raw processed images are very good. This is with the 16-50mm F2.8 lens which is reported to be much better than the 18-55 kit lens.