<p>Jim, I can't specifically address your question since I've never used it on a T3i (I have one, just haven't mounted the 150-600 on it). Even on my gripped 5DIII, it feels a little nose heavy, so I'm sure Marcus and David are right about the off-balance feel. </p>
<p>I suspect you will like the 150-600, although you don't indicate why you want this lens. I shoot static, or nearly so, subjects (mainly wildlife) in decent light most of the time. For the cost, it is a fine and versatile lens. I think the IQ is on a par with the Canon 100-400. And the extra 200mm of FL is terrific for shooting birds and other small subjects.</p>