Assuming you are stuck inside a lot during the winter (otherwise I'd suggest gobs of "real" riding as being a far more important component of improving your cycling than either rollers or a CT)...if you are seriously considering spending $1300+ on a CT, then why not get both - a good used set of rollers would probably only set you back another $150-200. Rollers are terrific and will really help your pedal stroke but can get tedious for longer indoor sessions, it's harder to stand up, takes a while to get to where you can ride them on the aero bars, etc. The variable, programmable resistance of the CT is nice, and it's also a way of measuring progress...keeping in mind neither will magically make you a good bike rider, they'll just improve certain aspects of your riding toolkit.