I haven’t ridden it, but I suspect the Allez Sprint is going to ride rough. It’s deep section aluminum, which is going to be tend to be rigid. Crits generally are all about the high power sprints and breakaways, so it’s likely designed extra stiff. Not ideal for long rides. That said, I would much rather crash an aluminum frame than a carbon one.
The Tarmac is designed to balance speed and comfort with speed still being the main goal (not a total endurance bike).
Tires and tubes can go a long way towards comfort. Vittoria Competition latex tubes are amazingly smooth rolling. Pair them with a supple 28 mm tire and any bike will ride really nice as long as you’re not hitting potholes.
How big of a tire do you want to run? Keep in mind you should consider true width. GP4KII are notoriously larger than labeled. GP5k are closer to labeled size, but rim width affects all tires.