Maybe too late, but I recently upgraded from a Panasonic FZ150 to a Sony A58. I've taken 100s of 1000s of pics with bridge cameras; from the Fuji s8100d to Panasonics FZ28 - 45 - 150. The weight and convenience of a bridge camera has meant I'd not considered a DSLR/T before, but for a number of reasons I changed my mind.
The main advantage so far is speed of auto focus, and an EVF that's 4* the size of most bridge cameras; oh, and the EVF is OLED, so it's bright and clear. The A58 is limited in functions compared to what I'm used to, but I've read that this isn't the case with the more expensive Sonys (65/77). IQ is a better, but not as much as you might think. Noise at high ISOs is better too, but again, maybe not as much as you might think, until you get past ISO 800.
The main disadvantage is reach. I'm used to getting 1020mm focal length with a TCON17 attached to the FZ150; ATM I've only 300mm equivalent (55-200mm).
Anyway, I've not had the camera for two weeks yet; have a look at the last 9 pics in my gallery, starting with this one:
http://www.birdforum.net/gallery/showphoto.php/photo/507689/ppuser/69033
All apart from the Gull in flight taken through double glazing and at slow shutter speeds (in camera IS is pretty good)
I've also attached one full frame image taken at ISO 3200 through double glazing and in poor light. I've done nothing except adjusted the levels slightly and resized for upload... no sharpening or noise reduction.
I'll let you know if I made the right choice if I get a chance to test the camera properly at my local reservoirs... providing the light is better