I used an LTC1250 Op Amp and got excellent results also added low pass filter to output cutoff 16HZ. I use it to observe micro Volt signals on a scope or handheld DVM. My measured noise was 9nV/ square root HZ or .4 uV PK-PK. I can easily see 100 nano Volt resolution with an extech meter confirmed against an Agilent 3458A and a Krohn-Hite 523 calibrator.
