I've test driven it. I don't think the noise is excessive but like any budget small car it could be better, especially if you like listening to music. I'ts nothing that a couple hundred dollars worth of Dynamat or other sound proofing can't fix. What I suggest you do is if you have a smart phone, download an app that measures Sound Pressure Level (SPL) in Decibels. I use "Sound Meter" for Android phones. Calibrate it in a quiet room, then go measure your car while you drive and get an average on different road surfaces. then use it while you test drive other cars you are considering.
According to Car & Driver Magazine, the 2018 Fit averages 71 decibels at 70 mph on an average freeway surface. This is pretty much the same as many other cars in its class (Fiesta, Accent, Versa, Rio). A 2008 Ford Focus is about 1dB louder than the new Fit so I can't imagine that the older ones are any better, but the new focus measures at 67dB, which is about half as loud as the Fit (every drop of 3dB reduces apparent loudness by half). Just for comparison, a new Chevy Volt in electric mode is 68dB, while in petrol mode is a bit over 73, one of the louder cars on the market. S new Civic weighs in at 67dB.