for the most part...the main difference in park boots is simply marketing.
however, there are things such as more shock absorbent liners/boot boards...rubber toe boxes(decrease to bang), and larger power straps.
in my experience, freestyle boots are more comfortable...HOWEVER. (and this is HUGE). If the boot doesnt fit...it wont matter how much the boot was...and how many of ur favorite pros ride them...they WILL hurt when skiing them.
what i would reccomend for you, is go to a local ski shop where you can have a 1 on 1 interaction with a boot fitter. ESPECIALLY since you are getting in freestyle skiing, it isnt nessisary for you to get a freestyle boot, however if you find one that FITS, then without a doubt, pull the trigger and snatch em.
just dont go into a shop with the mindset that only a certain make/model is going to work.
because depending on the width of your foot, instep height, foot thickness, etc...will completley change the shell category that you will fit into.
if you have any questions on this, feel free to pm me.