HSMXpress is literally a subset of HSMWorks, so everything you do is applicable. Now in HSMWorks you do have the 3D machining strategies that (sort of) obsolete the 2D strategies in HSMXpress, but the 2D strategies are still available in HSMWorks and are useful at times. Otherwise they are exactly the same. In fact HSMXpress can even open and view HSMWorks tool paths; it just can't edit them.
Also, if you want to get a feel for the 3D strategies you could try Fusion 360. It's not integrated with Solidworks but you can get it for free on a hobbyist/startup license to try out, and then upgrade to the commercial license later. Fusion uses the same CAM system as HSM but has its own CAD system that is similar to Inventor. Coming from Solidworks it's a little weird but it has incredible functionality for the price.
I actually use HSMXpress most of the time (most of my parts are 2.5D) and really only use Fusion when I need true 3D machining. I don't do enough 3D machining to justify buying a license for HSMWorks.
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