Pretty good

Battery alerts were why I got this app and they work well. I have some suggestions:
- config low batt percentages
- unique or configable low batt alert sound
- wifi / 3G loss alert is too sensitive. Needs to have a delay or more hysteresis (eg transition needs to last longer than x seconds) so a spotty area doesnt cause 10+ loss of signal alerts in a few seconds.
- have it possible to start automatically after phone reboot. I keep forgetting to start it.

Update: under iOS5 the alerts can be configured as banners that stay out of the way, so that is no longer an issue.

Lvn1119 about Signal Alert, v4.1