In the last 5 years Ihave used 14.04 and then 16.04 some 5% of my “laptop-time” and now I just follow-up the evolution of things, I’m no big expert.
The good? A 10 year support will mean for many users that they will not have to go though the struggle of going to a new version before long. Granted that going from 16.04 to 18.04 was no big deal for experienced user but many people just want to “press the button” and use their machine. For those everyday users, having to open a “black” window to type instruction copied from help gathered online is not what they want.
The bad? I tried 18.10 Cosmic Cuttlefish. I like the look and feel of it. Announced that it will better manage battery power. Will such interesting feature be retroactively implemented also on 18.04 updates or only for future version? If not, then users of 18.04 are stuck with what they have. My guess is that they will probably not notice or mind such thing.
Until now, Ubuntu releases a new LTS version every two years. If they continue to do so I see no impact for people who want to use newer features. If Ubuntu change that policy and does not release a 20.04 LTS version but goes to 21 or 22, then I think many “more daring” Ubuntu users will be disappointed.