I am not any kind of tax expert or other financial advisor, but my layman's understanding is that, for holding a position over multiple years in an taxable United States account, S&P futures contracts have what, in such a case would be a substantial disadvantage: taxation under Internal Revenue Code (that is, United States Code, title 26), section 1256, which treats gains as 60% long term, 40% short term, regardless of hold time, and requires all positions to be marked to market at the end of the year (that is, treated as if they were sold at the end of the year and immediately repurchased, with no wash sale rule). So you would lose not only 40% of the benefits of the long term capital gains tax rate, but also the compounding tax advantage of holding an investment over multiple tax years.
On the other hand, if you are trading a tax advantaged account that offers essentially no margin on stocks but does for futures, then that might be what you want (as long as you understand the risks), in which case you should be able to reduce the number of trades you make by buying futures that expire later. For example, I see that the September 2018 ES futures contract currently has a bid-ask spread of one tick (0.25 tick size x $50 contract multiplier = $12.50).