First, Sony is not remotely behind in high ISO compared to any other manufacturer - in fact they currently make the market's best APS-C sensor for high ISO performance, and in the A580 they are essentially equals at the top with the K5 and D7000 which share the same sensor. Combine the fact that Sony is the only one allowing multistacking high ISO shooting, and they're actually miles AHEAD at the highest ISO levels. I shoot a lot of high ISO, and I shoot at ISO6400 regularly with both my A550 and NEX5 and use it for prints comfortably - I've not seen another APS-C camera deliver significantly better ISO6400 results and the A580's sensor is even better than mine.
you people can't aqsually find a super advantage in the high FPS of the Sony cameras. I mean,yes pro bodies shoot 8-11 FPS,but so does superzoom compacts.
There is a huge difference in the usefulness of a fast frame rate between DSLRs and compacts. First off, I can shoot 7 FPS on my A550 for several dozen frames before the buffer fills and it slows down - on a superzoom with 10fps, you can shoot exactly 10 frames for 1 second, then sit waiting while the buffer clears before takng another shot. I can shoot at 5 FPS with full exposure and focus tracking for 35-45 frames on a moving target, which you cannot do with a superzoom. As for good AF systems - 'good' is not measured by how many focus points you have or how many cross-type points you have, but on how accurate and effective the system is in achieving reliable focus and tracking. I have extensive experience with Sony's A5xx series AF systems in shooting moving targets and relying on the speed and accuracy of the AF system, as well as it's ability to track focus...and I can tell you it is not modest, but actually extremely good. I can focus on moving targets with near-100% accuracy, the focus speed is as fast and reliable as any other APS-C camera I've shot next to, and I can track a moving target with the AF system at closing speeds of 20+ MPH with a 420mm lens.
You may find a disadvantage of the 'dark' viewfinders (of which they are the same as other APS-C entry bodies), but others do not. I have never struggled with entry-level mirror viewfinders, even wearing corrective glasses - some folks need the big pentaprisms to see well, some don't. I simply don't - I can see, focus, and expose perfectly with smaller viewfinders. Sony live view is indeed amazing, and it doesn't really restrict the viewfinder any more than any other APS-C entry-level camera from Nikon or Canon which have the same viewfinder size. I for one will take the smaller viewfinder every single time in order to get Sony's live view system - it is specifically what make Sony's DSLRs so vastly preferred and superior for me to any other. When shooting birds, wildlife, or action, I use only the viewfinder on my A550, and I can focus as fast, as accurately, and track as well as any other APS-C camera on the market...arguably better in fact, as I've found occasional issues with accuracy of the AF systems on some other brands of DSLR - whereas I've not heard of a Sony DSLR having AF accuracy issues.
The problem with sweeping statements is that they are never true. If YOU specifically have issues with the viewfinder size, or don't like the live view compromises, or have experienced problems tracking moving targets with a Sony focus system, those are your experiences, not everyone's. While I know what I can do with my Sony camera, I also know that others may not have the same experiences or opinions. I hope that some part of my ability has to do with a modicum of skill or experience, but much credit still goes to the camera's systems for being able to keep up.
As an example of how much experience, skill, technique, etc go into the process - I've shot many times with friends who use other systems...some of which have those enormous 51-point focus grids with 15 cross points and predictive servo tracking etc...and I'll stand beside them with my 11 focus points and 1 cross center point using AF-C. My every technical measure, their focus system is 'superior' to mine, yet a bird flies towards us, and I've got my lens up, achieve focus, begin firing at 5fps, and track the bird in easily, while my friend can't seem to get one clear shot. Not because my camera's better or his is worse, but because despite all of the impressive stats about his focus system, he still needs to achieve the initial focus to begin tracking, and either struggles with it, or the lens hampers him, or he doesn't know the proper camera settings, or he just doesn't have the skill and practice.
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 150-600mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony A6000 / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / 10-18mm F4 / 35mm F1.8 / 16mm F2.8 / via manual adapter, lots of Pentax K mount, Konica K/AR mount, and Leica M mount manual lenses