PHP在本地WAMP服务器上不使用SMTP发送邮件

I'm working on PHP send mail. Here I have using send mail and I have done all local setup Sendmail path but still not getting any mail. what might be the problem here. I don't want to use SMTP(). Below is my sample code. Can you suggest me 1) With SMTP 2) Without SMTP which one is the better choice?

<form action="form.php" method="POST">
Mail to:   <input type="text" name="to"><br>
Subject:   <input type="text" name="subject"><br>
Message:   <input type="text" name="message"><br>

<input type="submit" value="SEND">
</form>


<?php
  $to=$_POST["to"];
  $subject=$_POST["subject"];
  $message=$_POST["message"];

  $mail = mail ($to, $subject, $message );
       if($mail == false){
         echo 'Mailer Error ';
       }else{
       echo 'Message has been sent without using SMTP.';
      }
   ?>