For purely aesthetic reasons I went from a Rythmik F12G with paper-based driver to a Classic 98. Their sound profile is more similar than different - they were both a little more rounded with not as much punch, but both integrated well. The F12G dug deeper with exponentially more tuning capability which I played around with for three years. This is the weakness of the 98, especially since it doesn’t have variable phase. Beyond aesthetics, and only speaking for myself, one of the greatest strengths of the 98 is actually SpeakOn cable and the flexibility it provides if you don’t have a sub output or want to utilize high level input on the sub.
From a SQ perspective there’s differences between both subs, but I definitely don’t regret selling the F12G and purchasing the 98. For what it’s worth and YMMV.