Opinions on MLS properties??

[Dan Schweit]

What are your thoughts on MLS listed properties (Redfin, Zillow, Realtor)? Does anyone find good deals this way? As soon as I find what seems like a deal I pause and wonder why, if it is a good deal, was it not snatched up prior to listing. Mind you i'm a beginner and am making the assumption that it was brought to a more seasoned investor before the agent decided to list. Is this just analysis paralysis or is there strong validity to this thinking?