I would expect the Allez to fit "bigger", in that the head tube is a bit further foreward of the bb shell, due to the steeper seat tube.

This assumes each bike has the same top-tube length.

Further, the Allez' steeper head tube angle should support a slightly longer stem before the handling is compromised, while (again due to the steeper head tube angle) a shorter stem would more-readily cause twitchy steering on the Allez than on the Sirrus.

The Allez' steeper angles are intended to support a more-foreward rider position that is appropriate to both a higher pedaling force and a more-aero tilt to the rider's upper body.

The Allez' shorter wheelbase, as described, can only be attributed to a less-raked fork, which helps balance out the steeper head tube angle's reduced trail and also allows the rider to draft more closely to the wheel of the rider in front.

The Epic will make the more effortless climber, if the saddle is set foreward, since the climbing/sprinting stance will be less of a "heave" effort up from the seated position. The rider can thus more-effortlessly and more frequently transition from seated to standing and back, to better handle changes in road pitch without loss of speed.

Lastly, the Allez' steeper angles would in itself make the ride slightly harsher and the steering would likely feel more responsive, i.e. less stable.

I think that's about it. I would consider a larger frame for your height if your (saddle) position on the bike is far enough foreward, i.e. if you like pedaling hard, as on shorter and/or higher-effort rides.
I'm a fairly long-legged 5'9" and here would select a 58 or 60cm Sirrus with a zero-offset seatpost, but my preferred setups look like these, with a decent bar height being part of the equation for riding hard/fast comfortably for hours at a time. No short wheelbases here!: