This could just be a matter of adapting to the differences of how an EVF system works - the EVF of the Sony SLT models is much different from that of a P&S camera, and it is changeable as to settings for exposure simulation or not...also, the camera's focus system operates identically to a DSLR, so it should perform no differently in low light. The sensor in the A55 is one of the top-rated DSLR sensors on the market, with the A55's translucent mirror costing roughly 1/3 of a stop of light.
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May I ask precisely what model of Sony you are currently using? There are several upgrade possibilities that may work for you - note the A55 is a bit old-in-the-tooth, having been released over a year ago - the newer A35, 65, and 77 also use EVFs, but there have been slight changes to the tech, and the EVFs on the A65 & A77 are 2nd gen - said to be much better than those on the A55s.
Also, there is a Sony DSLR model that came out the same time as the A55, one with a traditional optical viewfinder and flipping mirror - and also with the same excellent 16MP sensor that resides in so many models of camera nowadays...the A580. It may end up being Sony's last traditional DSLR, but also allows you to get current modern tech, top of the line sensor, and heavily upgraded focus speed, buffer, battery life, focus points, etc than most previous Sony DSLRs and current SLTs. And with much of the future pointing to EVFs being more and more common, they will continue to work on the current flaws and compromises so future generation EVFs can legitimately replace the OVF for a majority of shooters. The A580 is available at excellent prices, and very likely represents a serious upgrade for the type of shooting you intend to do (battery life CIPA rated over 1,000 shots, huge buffer for continuous shooting, 5fps burst shooting with full focus & exposure, or 7fps speed burst with fixed focus, the best live view system of any DSLR with phase-detect AF and full burst capability in live view, tilting LCD screen, expanded focus points over previous model with additional cross sensors, and excellent high ISO performance for low light shooting up to ISO12800, and a trick multistacking ISO mode, along with a raft of other features...all for around $800. Something to consider.