I think it worth investing in. The Masternode counts I have started logging: 10/2 448, 11/2 482, 12/6 486, 12/17 463, 12/27 471, 1/4 484. The block reward will drop in 115 days. ION has shown some resistance to following BTC dips. A Masternode right now will run you $68,000. Not many MN owners are going to break them down, since reentry would probably be too expensive. Ionomy and STKE.io offer services to get better stake rates than doing it alone in your wallet, unless you get a large number.  As the block reward size decreases, I believe the price will go up. Just my two cents worth, please base any investment decisions on your own research.

I find this chart a little easier to understand than others:
https://coinmarketcap.com/currencies/ion/