risk vs reward
My inclinations are similar to @James Wise if the comps are there and you can make 20-25k, and sell it quick with minimal headache, and I can get my money back to invest in something else, I would do that in a heartbeat.
I have done lease options, some worked but many of them ended poorly. Maybe you can sell the property for a few thousand more by doing lease option, but it is also very likely your buyer won't be able to get financed in a year, its very possible he will walk at that point and you have to sink money into the house again to sell it to another buyer.
In regard to making more money by not paying taxes as earned income.
Capital gains rates at 15% if in 25% tax bracket, on 20,000 profit gain is 2,000, while significant, to me the hassle, the delay, tying up my money, and the potential for greater loss if the buyer destroys the property... would not be worth the potential increase profit.
We all have different risk reward tolerances, cash needs, consider them then you can devide what's best for you.
Congratulations on completing a successful profitable flip!