Feastudy 6 is excellent (cost approx $700), then again so are excel spreadsheets.
Whatever you use, the output is only as good as your assumptions and data you input.
Both forms of feasibility are useless if you don't have a reasonable handle on the various costs associated including construction costs, end values and not to forget all the multitude of smaller add-ons including finance, fees, more fees and contingencies.
Good luck
Joe D