In a word, Yes. I have Rythmik, SVS and REL subs in my system and I am currently considering upgrading to all Rythmik subs. The Rythmik is a little tighter than the SVS and much tighter than the REL, which is due to the servo in the Rythmik instantly stopping the driver which greatly reduces if not eliminates overhang or blurring of the musics structure. The servo also helps the sub cycle lower with less rolloff.
Beware that the servo puts a lot of stress on the amp and the driver so you will need to make sure that the heat created by the amp has a place to go and that cone stiffness is of primary importance.
The Rythmik may help a little bit with the booming issue you are having, but that is primarily a room issue, best addressed with acoustic treatments, e.q., multiple subs or all of the above.
The mushiness is probably a frequency overlap issue between the sub and your mains and you should be able to correct that by lowering the the lowpass filter setting on your sub or by adding a high pass filter to your mains