They're all pretty good options and much of a muchness really! You may also want to look at Britax Dualfix, Besafe izi Turn, Nuna Rebl, Recaro Salia and Maxi Cosi Mica. I think my favourite for ease of use is the Britax i-size. I was not a fan of how you spin the Cybex one - you have to push the whole seat up, which is fine with a 10kg 1yo, but would be tricky with a 16kg 4yo. I also found because of that mechanism it tends to slip and move very suddenly, which I think would wake the child up if they are napping. Personally we have the Joie 360 Spin, been using it 3 years (now on the second child) and I am very happy with it. It is worth comparing with the others, because when in direct comparison with them, the Joie does feel noticeably "cheaper" - which it is - so I think that's OK but some people might prefer to pay more for a different model.
If you are on a budget, GracoTurn2Me is worth looking at as it is the same model as the original Joie 360 under the covers.
The only thing I'd say to avoid is any that transform into a booster seat as well. For some reason, adding that on tends to reduce the safety performance - I think because they end up doing too many "jobs" and it weakens it overall.
Other than that yes, get a test fit in the car to check front seat space (the Joie ones are the most compact) and test them out in the shop to see which DD looks comfy in and which are easy to use, spin, recline, harness etc. Well worth doing. If you have an independent baby shop near you, all the better. Google any baby stuff brand and look at their stockist list, then see if you notice any that aren't chains. I tend to find they pay more heed to the brand trainers and are more interested so take the information on board. Whereas your average car enthusiast or Saturday teen in Halfords might have no interest in child seats.
Then one more point about it lasting until 4 - check your DD's projected weight and height at age 4 based on her centile line(s) in her red book. The spinning seats tend to be suitable until approx 18kg and 105cm, with a few minor differences between them - some have a slightly larger weight capacity, and some pre-i-size seats have no height limit, which means you can use until their eyes are level with the top of the shell. Joie 360 Spin and Britax Dualfix (original) are the only ones left on the market now, out of those two the Joie has the taller shell.
If you're worried about her outgrowing it before age 4 based on these numbers, you might want to look at the ERF up to 25kg/125cm seats - Axkid Minikid, Britax Max Way etc. These can be even easier to use than the spin seats, and they last much longer.