When Spektrum first came out on the 2.4GHz band, they worked great.......for aircraft.
The issue was that a high VHF or UHF signal, which is where the 2.4 band is, are easily reflected by the surface of water. This caused reception issues that lead to boats going out of control and being damaged(or destroyed in one case that I witnessed) and people going back to the tried and true 27 and 75MHz systems. Futaba was able to figure out the problem and, when they released their 2.4GHz systems, they didn't have the same issues. This is where the anti-Spektrum sentiment came from.
Spektrum has since figured out how to fix these issues and has come out with what I've been told is a reliable system. Over the past few years, I see boaters using Spektrum systems but not to the extent I see using Futaba.
