I use CDONTS and it works fine for me. For example, this is a script that I use to mail a password reminder to a user that has forgotten login details:
Dim objCDO
Set objCDO = Server.CreateObject("CDONTS.NewMail"
' This code assumes the above CDO instantiation code is included
objCDO.To = email
objCDO.From = "pwadmin@mycompany.com ( Password Reminder)"
objCDO.bcc = "me@mycompany.com"
objCDO.Mailformat=0 ' Specifies HTML Message Format
objCDO.Bodyformat=0 ' Specifies HTML Message Format
Dim MailBody
MailBody = "<!DOCTYPE HTML PUBLIC ""-//W3C//DTD W3 HTML//EN"">"
MailBody = MailBody & "<HTML>" & vbcrlf
MailBody = MailBody & "<HEAD><TITLE>Password Reminder</TITLE></HEAD>"
MailBody = MailBody & "<BODY>" & vbcrlf
MailBody = MailBody & "Dear " & record.Fields("UserName"

& ",<BR><BR>"
MailBody = MailBody & "Your login details for the client area are as follows:<BR><BR>"
MailBody = MailBody & vbcrlf
MailBody = MailBody & "<TABLE BORDER=""0"" CELLSPACING=""2"">"
MailBody = MailBody & "<TR><TD><B>User ID:</B></TD><TD>" & record.Fields("UserID"

& "</TD></TR>"
MailBody = MailBody & "<TR><TD><B>Password:</B></TD><TD>" & record.Fields("Password"

& "</TD></TR>"
MailBody = MailBody & "</TABLE></BODY></HTML>"
objCDO.Subject = "Login Details."
objCDO.Body = MailBody
objCDO.Send
Mise Le Meas,
Mighty
