Short version: No.
There is nothing wrong with Rythmik. Brian is a highly respected designer and his Subs have been among those highly recommended by just about everyone. Jim Salk even uses Rythmik Drivers in his custom Sub builds.
Servo Technology was a boon many years ago before Driver Design and Speaker Design took many leaps forward due to better modeling programs. Modern high quality Drivers simply do not need Servos to control them, though. When you put such a Driver in a well designed cabinet and give it good quality clean power, it will perform at a very high level.
Lastly, this continuing myth about Sound Reproduction being different for Music or HT usage (and the same can be applied to Sealed v. Vented Cabinets) NEEDS TO DIE.
Sound is sound. Whether it is gunfire in John Wick 2, the sickest Drum and Bass track you can find, or the ambient background noise of Trinity Church at the beginning of Mining For Gold by the Cowboy Junkies: 3 completely disparate examples that all have one thing in common: they are all SOUND and any high quality Subwoofer will reproduce them well.
More than anything, I would urge you to consider stepping up in size and quality of Subwoofer beyond entry level models, regardless of how capable they may be.
That said, you are in the right place in considering buying 2 matching Subs.