I've been using a Dexcom G6 for about 4 months. I'll share my experiences in hopes that they help someone.
TLDR; It's not all "sunshine and roses" but I'd say that, overall, things are better than before I had it. Certainly my HA1C numbers are much better. I WAS getting 8s and 9s, now 6s and 7s. My wife says I am noticeably "less grumpy"... happy wife = happy life.
This thing is expensive - about half again as much as my insulin pump supplies cost.
Let me be clear, it's a very annoying device - sometimes waking me 6-8 times in a night. It beeps during meetings and especially when I am trying to talk quietly with someone. It beeps for low Bg, High Bg, Falling Bg, Rising Bg, Low battery, you're too far away from it, sensor is about to expire and probably a few other things I am not remembering. It's so annoying that I have nick-named it "little bitch." It seems like it is always complaining about something.
I find that I am sort of "micro-bolusing" now. Before the CGM I'd check my Bg, read 25 (450) and give myself 20 units, now the CGM beeps at 9.5 (170) and I give myself 4 units, then 30 minutes later 4 units more, and so on. The total insulin is about the same, but my Bg does not go super high anymore.... and I fiddle with everything MUCH more often. I do wish that it would track insulin-on-board; with all the small boluses it's very hard to keep track of the overlaps.
I've experienced WAY more lows than pre-CGM; occasionally 4-5 in one day. Having tighter control means I am "close to the edge" more often than I used to be. Raising the alert threshold from the default 3.1 (55) to 4.2 (75) helped. I live in the country so I sporadically do intense exercise - chopping firewood, that sort of thing - so when my Bg is falling, it's sometimes falling fast. I keep a jug of juice handy and, so far, no death (I hate it when that happens).
I've hooked it up to TidePool and it says I am having low Bg about 3-4% of the time; my endocrinologist says that's "pretty good" but I pointed out to him that I only need to die once and dead people have very good HA1C scores - apparently, he doesn't have much of a sense of humour. I am getting better at controlling it but there have been some scary times. Being prepared is essential.
As far as finger pricks go, I am doing many fewer. They are definitely not eliminated entirely but I sometimes go 24 hours without one. Before the CGM, I pricked 4-5 times every day. I don't miss them at all.
The CGM is not entirely trust-worthy. I could probably eliminate 50% of my remaining finger pricks if I had more confidence in the device. Of 12 sensors, I had one that never worked correctly (just gave sort of random numbers) and another that worked well for about 7 days and then sort of "lost its mind" (gapping and giving insanely incorrect readings). I also had one that just quit on day 9 but the remaining 9 sensors worked pretty consistently for the advertised 10 days. The moral here is "don't just do whatever the robot tells you."
The CGM literature says that 90% of the time it's within 20% of actual Bg and that's probably technically accurate. Two things about that though: 1) 20% error is quite a lot when your Bg is 4 (72) and 2) the OTHER 10% of the time can be quite troublesome. Other people on the forum have said that recalibrating helps but that has not been my experience; my experience is that a sensor that is significantly off just keeps going off, recalibrating only seems to help short term.
The 20 minute lag (CGM is about 20 minutes behind the meter) takes some getting used to. You need to always consider the direction and rate of change. That's not something that I ever thought about pre-CGM. The CGM has an arrow that is supposed to tell you direction and (roughly) rate of change; I am not sure how they calculate that but it's often incorrect. I now always look at the graph and decide for myself what the direction and rate of change are.
Considering the lag, the many small boluses, the direction and rate of change, carb to insulin ratios, effect of exercise, and etc., there's quite a lot of (fairly simple) math that needs to be done. If that's not something that you can do easily, then a CGM will make things much more complicated.
But I guess the most telling thing for me was when there was a mix-up in shipping my CGM supplies and I had to stop using it for about 10 days. OMG it was so hard! My expectations had been reset by the CGM and it was next to impossible to match them without the device. Once you get used to a CGM, it's very hard to go back to finger pricks alone.
For all of its foibles, inconveniences and expenses, I think it does actually "make my life better" which is what's really important.