MF'17, Long term investment? hum. This is a very long term hold prospect. I would say minimum 5 year hold to see any kind of major profit. Of course, holiday flips are always great and will sell if priced accordingly. The UCS 10179 climbed higher and higher...but the minute the rumors started about the '17 version the (reseller) price started the fall. In the past three months alone, the average price for 10179 has fallen from $4500 to $2500. This is expected. Why would anyone pay $2500 or more for a "NEW" set that is going to sell for $800?
Lego will make it again. Maybe again, in 2027 we see the 3rd version and the same cycle will repeat it self.
In the end, If you have money to invest in multiple sets (like I do) and are ok having $800+ sitting in a corner...then by all means do it. Good luck, Invest wisely & happy building.