Whether you switch to DS and genesis or not may depend a lot on how much money you want to sink into new content/characters/plugins.

Genesis is free, but I'm pretty sure the shapes(m4, v4 etc) all cost money as do the morph packages for genesis.  From my understanding while your clothes would fit a v4 genesis you wont save any of their built in morphs when transfering them to genesis.  Content going forward may have a certain ease of use factor with the morph following (honestly cannot speak to how well this works) but you definitly leverage your current collection better by sticking with your current set up and adding the two morph packages.

While the base version of DS is free you will have to shell out some bucks to get similar functionality as you have in poser (8?) via plugins and add ons.  Genesis itself seems to be a bit of a money pit so you really should consider how much you are willing to spend. Even if you do have significant money to spend I'd still suggest looking into an upgrade to Poser 9 or pro 2012 and weighing the pros and cons of that vs. genesis/DS.  I'd say it compares very favorably and is getting a lot of really great and inexpensive figure support