This project benchmarks various .NET MIME parsers for comparison purposes.
Parsing startrek.msg (1000 iterations):
MimeKit: 0.6989221 seconds
OpenPop: 25.3056064 seconds
AE.Net.Mail: 17.5971438 seconds
MailSystem.NET: 26.3891218 seconds
MIMER: 76.4538978 seconds
Parsing xamarin3.msg (1000 iterations):
MimeKit: 3.4215505 seconds
OpenPop: 159.3308053 seconds
AE.Net.Mail: 132.3044291 seconds
MailSystem.NET: 133.5832078 seconds
MIMER: 784.433441 seconds
How does your MIME parser compare?