These two appenders are very similar. It would make sense to merge the functionality into a single logger which would have an option to buffer the output.
For example, a "bufferSize" option can be added. If bufferSize is set to 10, then an email will be sent for every 10 logged messages. If bufferSize is set to 1, the appender will send an email for each logged message (like LoggerAppenderMailEvent) and if the bufferSize is set to NULL, then buffering would be unlimited (like LoggerAppenderMail).
I propose to merge the whole funtionality into LoggerAppenderMail and make LoggerAppenderMailEvent deprecated.