Both are accurate and will serve you well. I've handled and shot both, and the CZ is far better-built gun in terms of being solid.

The Tikka is very "plastic-y" and has a stock you either love or hate. Although in .243 Win it won't be a concern, the Tikka stock seems to really magnify recoil, as well. In fact, the one I shot in .270 Win was uncomfortable.

The CZ trigger is one of the best I've used, and the guns are ridiculously accurate right out of the box (the Tikkas are accurate, too). Unless the Tikka just felt 100% better to me in terms of fit, I'd go with the CZ, hands-down.