My 2 year old has the slightly more expensive AC1100 model. Couldn't live without it and I have complete peace of mind, had a few problems at start but I was using the wrong settings, once tweaked its flawless. Got another baby coming in November and will use and trust Angelcare again.
We had the AC401 with motion sensor. Brought more peace of mind than any camera or microphone ever could. It was very sensitive and worked flawlessly. As long as we didn’t forget to pause it :p
We dropped our handset on the floor and the screen was damaged... complained to them about the frailty of the item (it wasn't a bad drop by any means) and the best they offered was to replace it for about £40 (I should add we had the top of the range model at the time) so not great but was happy to pay it for the peace of mind it brings. Got woken up to the alarm going off a few times in the first few months so consider it a bargain whatever the cost.
We had an angel are sensor monitor for our little ones. It worked perfectly for 3 kids. Even survived my 18 month old putting the handset down the toilet. Excellent bit of kit.