With an 80hz / small crossover (Audessey will set it at 60hz and large btw)
-On axis it's clear and detailed, but off axis (and by that I mean like 50-60 degrees) you do sometimes strain to hear some whispered or breathy dialogue. Such is the fate of any Mid-Tweeter-Mid center speaker. With that said however it prolly does reduce interference with mains to have that sort of speaker design, so sound placement between the front stage is always well defined. It's all a tradeoff I guess.
-In pink noise at least, it doesn't quite sound timbre matched to the mains
-It's reasonably dynamic. True, I'm amplifier limited but about 8 feet away I don't hear much strain at reference level movie watching.
-I opened up the binding post cup and shoved a handful or two of polyfill in it. It seemed to take away a bit of chestyness that was present at first.
-I found I got very nice performance taping 8 layers of weather stripping onto the front feet to make angling stands. It put my ear on axis with the tweeter which I found made an audible difference.
So my advice? Go with an E5Ti center if you somehow can, but if you're limited, the E5Ci is a nice center. If aesthetics matching or perhaps budget are not the biggest concern, look into a quality WMTW center... I'd bet the Revel C12 would be great with those mains!
Anyways, I don't know about the E5Tis, but the E55tis have a detailed yet laid back top end. It'll never be in your face but it'll always be present and pleasant.