I assume you are refering to the Dynavector DRT XV-1S?
(You wrote DX-1S, and I don't think there is such a cartridge.)
I have not used the Shelter 7000 or the 9000, but I did use the 90X for a couple of years. If great bass response is your priority, (and saving money while you're at it), it might be the cartridge for you. It is a near reference quality cartridge, IMHO. It has a well extended treble response, a very nice, and somewhat warm mid-range, and a great bass response. The imaging and soundstaging are also very, very good. The one knock on this cartridge is that it does not present really deep, dark, black backgrounds. (Which is not to say it has a really high noise floor. It is pretty quiet, but it is not as low a noise floor as some of the other really great cartridge lines, such as Koetsu or Dynavector. It is more middle of the pack, IMHO.) Unfortunately for me, I had used a couple of Koetsu cartridges for a couple of years prior to using the Shelter, and so I knew what having a really, really low noise floor, and I really valued that aspect of the Koetsu cartridges.
The Dynavector XV-1S is the cartridge I upgraded to after the Shelter 90X, and I have no regrets whatsoever. The XV-1S has great bass response too. (Maybe not quite as deep, but it seems more refined and slightly quicker and tighter.) The mid-range is very natural sounding, and integrates with the well extended treble, (which is a bit more refined than the 90X), in a more balanced way. The imaging and soundstaging are incredoble. And, best of all, it has a very low noise floor, so I have those deep, dark, black backgrounds that I love so much. This is the cartridge I plan on living with for a very long time.
Well, I hope that helps.
Good Luck in your search!