I disagree with CarbsRok. My basals are spot on, I've fasted & fasted to prove it yet I still get double figures after every meal & many many hypos 4-6 hours later plus no consistency.
I am currently using CGM to try & sort things out. I self fund, but was able to persuade my consultant to agree a new pump with CGM capability so at least I had a chance. I am lucky that I can afford it, within limits. The consultant wasn't even prepared to consider NHS funding for me, though, if I can make it work well, I may have a case to persuade them. (I've had CGM for 2 months only so far)
I use the Medtronic Paradigm. The transmitter & 5 sensors were (if memory is correct) £775 or £685 if ordered with the pump. I tried to organise with the hospital to order together to save me money & as a result, they gave me the transmitter & 5 sensors free (don't know how that happened, but I wasn't going to complain).
Sensors cost £275 for 5 or £525 for 10. They expire after 6 months, so you can't buy 10 & only use once a month. I'm told that the transmitter should be good for a few years.
It is helping, some. I do find that the sensor can be a way out sometimes, particularly at night it seems to read on the low side saying I'm hypo when my meter says I'm OK.
It isn't CGBM, it reads interstital fluid, not blood. It runs about 15 mins behind blood glucose. I don't use the predictions as I find them annoying, but you set personal high/low limits so the pump alarms only when you reach the limit (and you can set different ones at different times of day) so if you set it to e.g.4.2, as long as your BG isn't falling really quickly, you can act before you go hypo.
I have found that it has made things worse in one respect: when I know I'm high, I want to correct & use the wizard to suggest a correction, but, as I have shown my HCPs so often, if I'm not at 12-14 after a meal, I'll be hypo 5 hours later. If I do correct, I end up overcorrecting & going hypo anyway. I'm trying to work on the lows & ignore the highs (as long as my BG comes back to normal within 5 hours) as it's the hypos which cause me the mist grief at the moment.
I'm using my phone now, so a really long post isn't easy, but can provide further info another time if you have specific questions.