Medium Plush or medium mattress? Innerspring or hybrid

So when I went to mattress firm today, I found out that I really like the feel of medium plush mattresses. However, I'm worried that it won't last over time due to it starting off soft already. The salesman said that you can always make a hard mattress soft but its not so easy to go back over time. Would it be better to go with the medium mattress in this case. I'm sleep in all three styles including on my back, on my stomach, and side sleeping. I also tend to get hot while sleeping. Is it worth to consider a hybrid over an innerspring?

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Edit: The beds I liked there was beauty rest pressuresmart 2.0 plush pillowtop 13.75" mattress https://www.mattressfirm.com/pressuresmart-20-plush-pillow-top-1375-mattress/5637368834.p?variantid=5637369621 , sealy 12" plush mattress https://www.mattressfirm.com/by-sealy-12-plush-mattress/5637297577.p?variantid=5637296104 , and serta iseries hybrid 1000 medium mattress https://www.mattressfirm.com/iseries-hybrid-1000-12-medium-mattress/5637145617.p?variantid=5637156229 .

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As far as order of beds, I liked the hybrid the best but its completely out of my budget followed by the sealy plush mattress and the pressuresmart pillowtop mattress. I'm 170 lbs. Some neck and back pain as well.