Libre

Just wandered what people's thoughts are on the libre ? I've found mine brilliant but tonight I've realised its maybe not quite as good as I first thought. The issue I've realised is that because there is a 15 minute (20 minute + on mine) delay between finger prick and libre, it actually means that the results when changing fast (I.e. Going down fast or up fast) can leave you with problems. I had a hypo yesterday and didn't know about the lag at the time. I treated it... Waited 15 mins checked on libre. Still hypo. Confused - I Treated it again and checked 5 mins later. Barely moved. Treated again and then checked finger prick. I was shooting way up, while the libre was well behind ! The downside is I ended up sky high for hours after !
My concern is also that it could work the other way around too.. I.e. Dropping quickly and be showing higher on the libre than what you really are.