Theres very little difference between the 750ss and the 7500ss. In the 750ss the main gear is held on with a screw located under the bearing cover opposite the handle.It also has the older torpedo style handle.
They are both decent reels provided they don't get wet or sandy. I just sold 3 of mine on E-bay last month( two 7500's and one 750.) They all fetched around $75 apiece without boxes or papers. Prices for those spinfishers can be estimated by taking the first 2 numbers on the reel and adding a dollar sign. For example: a 650/6500ss is worth about $65, a 750/ 7500 ss is worth about $75, 850/8500ss is worth $85 etc. Add $10-15 for a really nice example and subtract $10-15 for a used one with paint loss.
I sold all my newer model spinfisher reels on E-bay in the last 4 months because I never use them.(15 in all) They are prone to breaking down at the worst possible times because of all the small exposed parts underneath the rotor cup. A tiny amount of sand and water renders them useless in no time at all. I think they would make good boat reels however.
I'm hooked on the Z series reels from Penn. A much tougher reel that will grind sand if you ask it to.