I don't know what to tell you. One person's bright is another person's laid back. Another person's laid back is another person's neutral. One person's "just right on that cymbal" is a another person's "that cymbal should be bigger, more grand, more enveloping"
All I can do is show you facts, not opinion:
Infinity Primus Waterfall shows me it's a relatively good speaker, with some stored energy at 3khz and 5khz. If you do end up hearing this, take advantage of my advice wayyyyyyyyyyy back like a week ago: that you need a return option WHATEVER YOU BUY.
Infinity Primus On-Axis response
Below 300-400hz we're into room affects so we can't judge the bass as this is an in room measurement but above that it looks pretty neutral to me. Not the highest resolution graph in the world but it also shows that there's no broad rises in frequency that might emphasize highs over mids and bass.
Off-Axis response
For a 300 dollar speaker that's ridiculously good.
PSB Image T6
Seriously dude, buy something and take advantage of the damn return period if it doesn't float your boat. Worst comes to worse, use auto-EQ to flatten out the response.
EMP Tek e55ti
Looks like a flat speaker to me, with some oddness around 600hz and 1.3khz that TLS Guy thinks is stored energy but we don't know for sure because gene didn't measure that sort of thing. I'm not hearing the major effects and I think this speaker sounds pretty relaxing and detailed to my ears.
Revel F12
Energy RC-70
SVS STS-02
Moral of the story: unless I'm mistaken, you're coming from Polks. None of this stuff is that bad. Whatever you pick will be an upgrade. Don't overanalyze. If you don't like it, return it. Get something with a return period like the svs or aperion speakers and worst comes to worse you wasted a few days auditioning a speaker that didn't float your boat.