If it wasnt cleaned its about a $500 coin but being cleaned its probably $400. Depends on the buyer. Its a good mint/date.
Heck yours looks way better than this XF40! http://www.ebay.com/itm/1875-S-20-cent-PCGS-XF40-/330826885911?pt=Coins_US_Individual&hash=item4d06d1ab17
A certified F12 in a problem-free NGC or PCGS holder is a $400-$450 coin, so I would imagine you would have to come down a bit to sell one that looks like this.
I disagree also, the xf-40 coin has more pronounced features and sharper detail. The xf-40 has discoloration (which I'm not a fan of) but I think it's a nicer coin.
I could be wrong but I'd rather have the OP's, the Carson City mint is alot better looking than that ugly looking S. The obverse on the XF40 looks better and the reverse may be a tad better but the discoloration on the reverse makes the XF40 look real shabby. Bottom line, between the two, I still prefer the OP's.
Well both are beautiful coins, but the uncleaned one is more valuable and has more detail. Not to put your coin down machete, I like yours too, and I know not to make a guy with a name like machete angry.