Answer by Wray Rives:
Buyer is able to step up the basis of shorter lived assets, resulting in quicker depreciation and offering a tax advantage with lower taxes in the early years post acquisition.
Asset sales usually result in higher tax for sellers because some categories of assets are subject to ordinary income tax rates on gain from the sale.
Also if the business is a C corporation, then sellers will face double taxation. The corporation pays tax on the gain and the owner pays tax on dividend income when proceeds of the sale are distributed. S corporations may also face built in gains tax on sales.
In a stock sale the buyer does not get to step up the basis of specific assets in order to re-depreciate those assets. This typically results in higher post-acquisition tax liability.
Seller's get capital gain treatment on total gain, which will typically make a stock sale more attractive to a seller and result in lower tax on the transaction and potential corporate level tax is avoided.
That is strictly a US tax perspective and there are any number of other business and liability issues involved in an acquisition.